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math::statistics - Basic statistical functions and procedures

Bugs, Ideas, Feedback

       This  document,  and  the package it describes, will undoubtedly contain bugs and other problems.  Please
       report    such    in    the    category    math::statistics    of     the     TcllibTrackers
       [http://core.tcl.tk/tcllib/reportlist].   Please  also report any ideas for enhancements you may have for
       either package and/or documentation.

       When proposing code changes, please provide unifieddiffs, i.e the output of diff-u.

       Note further that attachments are strongly preferred over inlined patches. Attachments  can  be  made  by
       going  to the Edit form of the ticket immediately after its creation, and then using the left-most button
       in the secondary navigation bar.

Category

       Mathematics

tcllib                                                1.6.1                               math::statistics(3tcl)

Data Manipulation

       The data manipulation procedures act on lists or lists of lists:

       ::math::statistics::filtervarnamedataexpression
              Return  a list consisting of the data for which the logical expression is true (this command works
              analogously to the command foreach).

              string varname
                     - Name of the variable used in the expression

              list data
                     - List of data

              string expression
                     - Logical expression using the variable name

       ::math::statistics::mapvarnamedataexpression
              Return a list consisting of the data that are transformed via the expression.

              string varname
                     - Name of the variable used in the expression

              list data
                     - List of data

              string expression
                     - Expression to be used to transform (map) the data

       ::math::statistics::samplescountvarnamelistexpression
              Return a list consisting of the counts of all data in the sublists  of  the  "list"  argument  for
              which the expression is true.

              string varname
                     - Name of the variable used in the expression

              list data
                     - List of sublists, each containing the data

              string expression
                     - Logical expression to test the data (defaults to "true").

       ::math::statistics::subdivide
              Routine PM - not implemented yet

Description

       The  math::statistics package contains functions and procedures for basic statistical data analysis, such
       as:

       •      Descriptive statistical parameters (mean, minimum, maximum, standard deviation)

       •      Estimates of the distribution in the form of histograms and quantiles

       •      Basic testing of hypotheses

       •      Probability and cumulative density functions

       It is meant to help in developing data analysis applications or doing ad hoc data analysis, it is not  in
       itself a full application, nor is it intended to rival with full (non-)commercial statistical packages.

       The purpose of this document is to describe the implemented procedures and provide some examples of their
       usage.  As there is ample literature on the algorithms involved, we refer to relevant text books for more
       explanations.  The package contains a fairly large number of public procedures. They can be distinguished
       in three sets: general procedures, procedures that deal with  specific  statistical  distributions,  list
       procedures to select or transform data and simple plotting procedures (these require Tk).  Note: The data
       that  need  to be analyzed are always contained in a simple list. Missing values are represented as empty
       list elements.  Note: With version 1.0.1 a mistake in the procs pdf-lognormal, cdf-lognormal and  random-lognormal  has  been corrected. In previous versions the argument for the standard deviation was actually
       used as if it was the variance.

Examples

       The code below is a small example of how you can examine a set of data:

              # Simple example:
              # - Generate data (as a cheap way of getting some)
              # - Perform statistical analysis to describe the data
              #
              package require math::statistics

              #
              # Two auxiliary procs
              #
              proc pause {time} {
                 set wait 0
                 after [expr {$time*1000}] {set ::wait 1}
                 vwait wait
              }

              proc print-histogram {counts limits} {
                 foreach count $counts limit $limits {
                    if { $limit != {} } {
                       puts [format "<%12.4g\t%d" $limit $count]
                       set prev_limit $limit
                    } else {
                       puts [format ">%12.4g\t%d" $prev_limit $count]
                    }
                 }
              }

              #
              # Our source of arbitrary data
              #
              proc generateData { data1 data2 } {
                 upvar 1 $data1 _data1
                 upvar 1 $data2 _data2

                 set d1 0.0
                 set d2 0.0
                 for { set i 0 } { $i < 100 } { incr i } {
                    set d1 [expr {10.0-2.0*cos(2.0*3.1415926*$i/24.0)+3.5*rand()}]
                    set d2 [expr {0.7*$d2+0.3*$d1+0.7*rand()}]
                    lappend _data1 $d1
                    lappend _data2 $d2
                 }
                 return {}
              }

              #
              # The analysis session
              #
              package require Tk
              console show
              canvas .plot1
              canvas .plot2
              pack   .plot1 .plot2 -fill both -side top

              generateData data1 data2

              puts "Basic statistics:"
              set b1 [::math::statistics::basic-stats $data1]
              set b2 [::math::statistics::basic-stats $data2]
              foreach label {mean min max number stdev var} v1 $b1 v2 $b2 {
                 puts "$label\t$v1\t$v2"
              }
              puts "Plot the data as function of \"time\" and against each other"
              ::math::statistics::plot-scale .plot1  0 100  0 20
              ::math::statistics::plot-scale .plot2  0 20   0 20
              ::math::statistics::plot-tline .plot1 $data1
              ::math::statistics::plot-tline .plot1 $data2
              ::math::statistics::plot-xydata .plot2 $data1 $data2

              puts "Correlation coefficient:"
              puts [::math::statistics::corr $data1 $data2]

              pause 2
              puts "Plot histograms"
              .plot2 delete all
              ::math::statistics::plot-scale .plot2  0 20 0 100
              set limits         [::math::statistics::minmax-histogram-limits 7 16]
              set histogram_data [::math::statistics::histogram $limits $data1]
              ::math::statistics::plot-histogram .plot2 $histogram_data $limits

              puts "First series:"
              print-histogram $histogram_data $limits

              pause 2
              set limits         [::math::statistics::minmax-histogram-limits 0 15 10]
              set histogram_data [::math::statistics::histogram $limits $data2]
              ::math::statistics::plot-histogram .plot2 $histogram_data $limits d2
              .plot2 itemconfigure d2 -fill red

              puts "Second series:"
              print-histogram $histogram_data $limits

              puts "Autocorrelation function:"
              set  autoc [::math::statistics::autocorr $data1]
              puts [::math::statistics::map $autoc {[format "%.2f" $x]}]
              puts "Cross-correlation function:"
              set  crossc [::math::statistics::crosscorr $data1 $data2]
              puts [::math::statistics::map $crossc {[format "%.2f" $x]}]

              ::math::statistics::plot-scale .plot1  0 100 -1  4
              ::math::statistics::plot-tline .plot1  $autoc "autoc"
              ::math::statistics::plot-tline .plot1  $crossc "crossc"
              .plot1 itemconfigure autoc  -fill green
              .plot1 itemconfigure crossc -fill yellow

              puts "Quantiles: 0.1, 0.2, 0.5, 0.8, 0.9"
              puts "First:  [::math::statistics::quantiles $data1 {0.1 0.2 0.5 0.8 0.9}]"
              puts "Second: [::math::statistics::quantiles $data2 {0.1 0.2 0.5 0.8 0.9}]"

       If you run this example, then the following should be clear:

       •      There is a strong correlation between two time series, as displayed by the raw data and especially
              by the correlation functions.

       •      Both time series show a significant periodic component

       •      The histograms are not very useful in identifying the nature of the time series - they do not show
              the periodic nature.

General Procedures

       The general statistical procedures are:

       ::math::statistics::meandata
              Determine the mean value of the given list of data.

              list data
                     - List of data

       ::math::statistics::mindata
              Determine the minimum value of the given list of data.

              list data
                     - List of data

       ::math::statistics::maxdata
              Determine the maximum value of the given list of data.

              list data
                     - List of data

       ::math::statistics::numberdata
              Determine the number of non-missing data in the given list

              list data
                     - List of data

       ::math::statistics::stdevdata
              Determine the samplestandarddeviation of the data in the given list

              list data
                     - List of data

       ::math::statistics::vardata
              Determine the samplevariance of the data in the given list

              list data
                     - List of data

       ::math::statistics::pstdevdata
              Determine the populationstandarddeviation of the data in the given list

              list data
                     - List of data

       ::math::statistics::pvardata
              Determine the populationvariance of the data in the given list

              list data
                     - List of data

       ::math::statistics::mediandata
              Determine the median of the data in the given list (Note that  this  requires  sorting  the  data,
              which may be a costly operation)

              list data
                     - List of data

       ::math::statistics::basic-statsdata
              Determine a list of all the descriptive parameters: mean, minimum, maximum, number of data, sample
              standard deviation, sample variance, population standard deviation and population variance.

              (This  routine  is called whenever either or all of the basic statistical parameters are required.
              Hence all calculations are done and the relevant values are returned.)

              list data
                     - List of data

       ::math::statistics::histogramlimitsvalues ?weights?
              Determine histogram information for the given list of data.  Returns  a  list  consisting  of  the
              number  of  values that fall into each interval.  (The first interval consists of all values lower
              than the first limit, the last interval consists of all values greater than the last limit.  There
              is one more interval than there are limits.)

              Optionally, you can use weights to influence the histogram.

              list limits
                     - List of upper limits (in ascending order) for the intervals of the histogram.

              list values
                     - List of data

              list weights
                     - List of weights, one weight per value

       ::math::statistics::histogram-altlimitsvalues ?weights?
              Alternative implementation of the histogram procedure: the open end of the  intervals  is  at  the
              lower bound instead of the upper bound.

              list limits
                     - List of upper limits (in ascending order) for the intervals of the histogram.

              list values
                     - List of data

              list weights
                     - List of weights, one weight per value

       ::math::statistics::corrdata1data2
              Determine the correlation coefficient between two sets of data.

              list data1
                     - First list of data

              list data2
                     - Second list of data

       ::math::statistics::interval-mean-stdevdataconfidence
              Return  the  interval  containing  the mean value and one containing the standard deviation with a
              certain level of confidence (assuming a normal distribution)

              list data
                     - List of raw data values (small sample)

              float confidence
                     - Confidence level (0.95 or 0.99 for instance)

       ::math::statistics::t-test-meandataest_meanest_stdevalpha
              Test whether the mean value of a sample is in accordance with the  estimated  normal  distribution
              with  a  certain  probability.  Returns 1 if the test succeeds or 0 if the mean is unlikely to fit
              the given distribution.

              list data
                     - List of raw data values (small sample)

              float est_mean
                     - Estimated mean of the distribution

              float est_stdev
                     - Estimated stdev of the distribution

              float alpha
                     - Probability level (0.95 or 0.99 for instance)

       ::math::statistics::test-normaldatasignificance
              Test whether the given data follow a normal distribution with a  certain  level  of  significance.
              Returns 1 if the data are normally distributed within the level of significance, returns 0 if not.
              The  underlying  test  is  the Lilliefors test. Smaller values of the significance mean a stricter
              testing.

              list data
                     - List of raw data values

              float significance
                     - Significance level (one of 0.01, 0.05, 0.10, 0.15 or 0.20). For compatibility reasons the
                     values "1-significance", 0.80, 0.85, 0.90, 0.95 or 0.99 are also accepted.

       Compatibility issue: the original implementation and documentation used the term "confidence" and used  a
       value 1-significance (see ticket 2812473fff). This has been corrected as of version 0.9.3.

       ::math::statistics::lillieforsFitdata
              Returns  the  goodness  of  fit  to  a normal distribution according to Lilliefors. The higher the
              number, the more likely the data are indeed normally distributed. The test requires at least  five
              data points.

              list data
                     - List of raw data values

       ::math::statistics::test-Duckworthlist1list2significance
              Determine  if  two  data  sets  have  the  same median according to the Tukey-Duckworth test.  The
              procedure returns 0 if the medians are unequal, 1 if they are equal, -1 if the  test  can  not  be
              conducted (the smallest value must be in a different set than the greatest value).  # # Arguments:
              #     list1           Values in the first data set #     list2           Values in the second data
              set  #      significance     Significance  level  (either  0.05,  0.01 or 0.001) # # Returns: Test
              whether the given data follow a normal distribution with a certain level of significance.  Returns
              1 if the data are normally distributed within the level of significance, returns  0  if  not.  The
              underlying  test  is  the  Lilliefors  test.  Smaller  values  of the significance mean a stricter
              testing.

              list list1
                     - First list of data

              list list2
                     - Second list of data

              float significance
                     - Significance level (either 0.05, 0.01 or 0.001)

       ::math::statistics::test-anova-Falphaargs
              Determine if two or more groups with normally distributed data have the same means.  The procedure
              returns 0 if the means are likely unequal, 1 if they are. This is a one-way ANOVA test. The groups
              may also be stored in a nested list: The procedure returns a list of the  comparison  results  for
              each  pair of groups. Each element of this list contains: the index of the first group and that of
              the second group, whether the means are likely to be different (1) or not (0) and  the  confidence
              interval the conclusion is based on. The groups may also be stored in a nested list:

                  test-anova-F 0.05 $A $B $C
                  #
                  # Or equivalently:
                  #
                  test-anova-F 0.05 [list $A $B $C]

              float alpha
                     - Significance level

              list args
                     - Two or more groups of data to be checked

       ::math::statistics::test-Tukey-rangealphaargs
              Determine  if two or more groups with normally distributed data have the same means, using Tukey's
              range test. It is complementary to the ANOVA test.  The procedure returns a list of the comparison
              results for each pair of groups. Each element of this list contains: the index of the first  group
              and  that of the second group, whether the means are likely to be different (1) or not (0) and the
              confidence interval the conclusion is based on. The groups may also be stored in  a  nested  list,
              just as with the ANOVA test.

              float alpha
                     - Significance level - either 0.05 or 0.01

              list args
                     - Two or more groups of data to be checked

       ::math::statistics::test-Dunnettalphacontrolargs
              Determine if one or more groups with normally distributed data have the same means as the group of
              control  data, using Dunnett's test. It is complementary to the ANOVA test.  The procedure returns
              a list of the comparison results for each group with the control group. Each element of this  list
              contains:  whether the means are likely to be different (1) or not (0) and the confidence interval
              the conclusion is based on. The groups may also be stored in a nested list, just as with the ANOVA
              test.

              Note: some care is required if there is only one group to compare the control with:

                  test-Dunnett-F 0.05 $control [list $A]

              Otherwise the group A is split up into groups of one element - this is due to an ambiguity.

              float alpha
                     - Significance level - either 0.05 or 0.01

              list args
                     - One or more groups of data to be checked

       ::math::statistics::quantilesdataconfidence
              Return the quantiles for a given set of data

              list data
                     - List of raw data values

              float confidence
                     - Confidence level (0.95 or 0.99 for instance) or a list of confidence levels.

       ::math::statistics::quantileslimitscountsconfidence
              Return the quantiles based on histogram information (alternative to the call with two arguments)

              list limits
                     - List of upper limits from histogram

              list counts
                     - List of counts for for each interval in histogram

              float confidence
                     -  Confidence level (0.95 or 0.99 for instance) or a list of confidence levels.

       ::math::statistics::autocorrdata
              Return the autocorrelation function as a list of values (assuming  equidistance  between  samples,
              about 1/2 of the number of raw data)

              The  correlation  is  determined in such a way that the first value is always 1 and all others are
              equal to or smaller than 1. The number of values involved will diminish as the "time"  (the  index
              in the list of returned values) increases

              list data
                     - Raw data for which the autocorrelation must be determined

       ::math::statistics::crosscorrdata1data2
              Return  the cross-correlation function as a list of values (assuming equidistance between samples,
              about 1/2 of the number of raw data)

              The correlation is determined in such a way that the values can never exceed 1 in  magnitude.  The
              number  of  values involved will diminish as the "time" (the index in the list of returned values)
              increases.

              list data1
                     - First list of data

              list data2
                     - Second list of data

       ::math::statistics::mean-histogram-limitsmeanstdevnumber
              Determine reasonable limits based on mean and  standard  deviation  for  a  histogram  Convenience
              function - the result is suitable for the histogram function.

              float mean
                     - Mean of the data

              float stdev
                     - Standard deviation

              int number
                     - Number of limits to generate (defaults to 8)

       ::math::statistics::minmax-histogram-limitsminmaxnumber
              Determine reasonable limits based on a minimum and maximum for a histogram

              Convenience function - the result is suitable for the histogram function.

              float min
                     - Expected minimum

              float max
                     - Expected maximum

              int number
                     - Number of limits to generate (defaults to 8)

       ::math::statistics::linear-modelxdataydataintercept
              Determine  the coefficients for a linear regression between two series of data (the model: Y = A +
              B*X). Returns a list of parameters describing the fit

              list xdata
                     - List of independent data

              list ydata
                     - List of dependent data to be fitted

              boolean intercept
                     - (Optional) compute the intercept (1, default) or fit to a line through the origin (0)

                     The result consists of the following list:

                     •      (Estimate of) Intercept A

                     •      (Estimate of) Slope B

                     •      Standard deviation of Y relative to fit

                     •      Correlation coefficient R2

                     •      Number of degrees of freedom df

                     •      Standard error of the intercept A

                     •      Significance level of A

                     •      Standard error of the slope B

                     •      Significance level of B

       ::math::statistics::linear-residualsxdataydataintercept
              Determine the difference between actual data and predicted from the linear model.

              Returns a list of the differences between the actual data and the predicted values.

              list xdata
                     - List of independent data

              list ydata
                     - List of dependent data to be fitted

              boolean intercept
                     - (Optional) compute the intercept (1, default) or fit to a line through the origin (0)

       ::math::statistics::test-2x2n11n21n12n22
              Determine if two set of samples, each from a binomial distribution, differ  significantly  or  not
              (implying a different parameter).

              Returns the "chi-square" value, which can be used to the determine the significance.

              int n11
                     - Number of outcomes with the first value from the first sample.

              int n21
                     - Number of outcomes with the first value from the second sample.

              int n12
                     - Number of outcomes with the second value from the first sample.

              int n22
                     - Number of outcomes with the second value from the second sample.

       ::math::statistics::print-2x2n11n21n12n22
              Determine  if  two  set of samples, each from a binomial distribution, differ significantly or not
              (implying a different parameter).

              Returns a short report, useful in an interactive session.

              int n11
                     - Number of outcomes with the first value from the first sample.

              int n21
                     - Number of outcomes with the first value from the second sample.

              int n12
                     - Number of outcomes with the second value from the first sample.

              int n22
                     - Number of outcomes with the second value from the second sample.

       ::math::statistics::control-xbardata ?nsamples?
              Determine the control limits for an xbar chart. The number of data in each subsample  defaults  to
              4. At least 20 subsamples are required.

              Returns the mean, the lower limit, the upper limit and the number of data per subsample.

              list data
                     - List of observed data

              int nsamples
                     - Number of data per subsample

       ::math::statistics::control-Rchartdata ?nsamples?
              Determine  the  control  limits  for  an  R chart. The number of data in each subsample (nsamples)
              defaults to 4. At least 20 subsamples are required.

              Returns the mean range, the lower limit, the upper limit and the number of data per subsample.

              list data
                     - List of observed data

              int nsamples
                     - Number of data per subsample

       ::math::statistics::test-xbarcontroldata
              Determine if the data exceed the control limits for the xbar chart.

              Returns a list of subsamples (their indices) that indeed violate the limits.

              list control
                     - Control limits as returned by the "control-xbar" procedure

              list data
                     - List of observed data

       ::math::statistics::test-Rchartcontroldata
              Determine if the data exceed the control limits for the R chart.

              Returns a list of subsamples (their indices) that indeed violate the limits.

              list control
                     - Control limits as returned by the "control-Rchart" procedure

              list data
                     - List of observed data

       ::math::statistics::test-Kruskal-Wallisconfidenceargs
              Check if the population medians of two or more groups are equal with  a  given  confidence  level,
              using the Kruskal-Wallis test.

              float confidence
                     - Confidence level to be used (0-1)

              list args
                     - Two or more lists of data

       ::math::statistics::analyse-Kruskal-Wallisargs
              Compute  the  statistical  parameters  for  the  Kruskal-Wallis  test.  Returns the Kruskal-Wallis
              statistic and the probability that that value would occur assuming the medians of the  populations
              are equal.

              list args
                     - Two or more lists of data

       ::math::statistics::test-Levenegroups
              Compute  the  Levene  statistic  to  determine  if  groups  of  data  have  the same variance (are
              homoscadastic) or not. The data are organised in groups. This version uses the mean of the data as
              the measure to determine the deviations. The statistic  is  equivalent  to  an  F  statistic  with
              degrees of freedom k-1 and N-k, k being the number of groups and N the total number of data.

              list groups
                     - List of groups of data

       ::math::statistics::test-Brown-Forsythegroups
              Compute  the  Brown-Forsythe  statistic to determine if groups of data have the same variance (are
              homoscadastic) or not. Like the Levene test, but this version uses the median of the data.

              list groups
                     - List of groups of data

       ::math::statistics::group-rankargs
              Rank the groups of data with respect to the complete set.  Returns a list consisting of the  group
              ID, the value and the rank (possibly a rational number, in case of ties) for each data item.

              list args
                     - Two or more lists of data

       ::math::statistics::test-Wilcoxonsample_asample_b
              Compute  the Wilcoxon test statistic to determine if two samples have the same median or not. (The
              statistic can be regarded as standard normal, if the  sample  sizes  are  both  larger  than  10.)
              Returns the value of this statistic.

              list sample_a
                     - List of data comprising the first sample

              list sample_b
                     - List of data comprising the second sample

       ::math::statistics::spearman-ranksample_asample_b
              Return  the  Spearman  rank  correlation as an alternative to the ordinary (Pearson's) correlation
              coefficient. The two samples should have the same number of data.

              list sample_a
                     - First list of data

              list sample_b
                     - Second list of data

       ::math::statistics::spearman-rank-extendedsample_asample_b
              Return the Spearman rank correlation as an alternative to  the  ordinary  (Pearson's)  correlation
              coefficient  as well as additional data. The two samples should have the same number of data.  The
              procedure returns the correlation coefficient, the number of data pairs used and the  z-score,  an
              approximately standard normal statistic, indicating the significance of the correlation.

              list sample_a
                     - First list of data

              list sample_b
                     - Second list of data

       ::math::statistics::kernel-densitydata opt -optionvalue ...
              Return  the  density function based on kernel density estimation. The procedure is controlled by a
              small set of options, each of which is given a reasonable default.

              The return value consists of three lists: the centres of  the  bins,  the  associated  probability
              density  and  a list of computational parameters (begin and end of the interval, mean and standard
              deviation and the used bandwidth). The computational parameters can be used for further analysis.

              list data
                     - The data to be examined

              list args
                     - Option-value pairs:

                     -weightsweights
                            Per data point the weight (default: 1 for all data)

                     -bandwidthvalue
                            Bandwidth  to  be  used  for  the  estimation  (default:  determined  from  standard
                            deviation)

                     -numbervalue
                            Number of bins to be returned (default: 100)

                     -interval{beginend}
                            Begin  and  end of the interval for which the density is returned (default: mean +/-
                            3*standard deviation)

                     -kernelfunction
                            Kernel to be used (One of:  gaussian,  cosine,  epanechnikov,  uniform,  triangular,
                            biweight, logistic; default: gaussian)

       ::math::statistics::bootstrapdatasampleSize ?numberSamples?
              Create  a  subsample  or  subsamples from a given list of data. The data in the samples are chosen
              from this list - multiples may occur. If there  is  only  one  subsample,  the  sample  itself  is
              returned (as a list of "sampleSize" values), otherwise a list of samples is returned.

              list data
                     List of values to chose from

              int sampleSize
                     Number of values per sample

              int numberSamples
                     Number of samples (default: 1)

       ::math::statistics::wasserstein-distanceprob1prob2
              Compute  the Wasserstein distance or earth mover's distance for two equidstantly spaced histograms
              or probability densities. The histograms need not to be normalised to sum to one,  but  they  must
              have the same number of entries.

              Note: the histograms are assumed to be based on the same equidistant intervals.  As the bounds are
              not passed, the value is expressed in the length of the intervals.

              list prob1
                     List of values for the first histogram/probability density

              list prob2
                     List of values for the second histogram/probability density

       ::math::statistics::kl-divergenceprob1prob2
              Compute the Kullback-Leibler (KL) divergence for two equidstantly spaced histograms or probability
              densities.  The  histograms  need  not to be normalised to sum to one, but they must have the same
              number of entries.

              Note: the histograms are assumed to be based on the same equidistant intervals.  As the bounds are
              not passed, the value is expressed in the length of the intervals.

              Note also that the KL divergence is not symmetric and that the second histogram should not contain
              zeroes in places where the first histogram has non-zero values.

              list prob1
                     List of values for the first histogram/probability density

              list prob2
                     List of values for the second histogram/probability density

       ::math::statistics::logistic-modelxdataydata
              Estimate the coefficients of the logistic model that fits the  data  best.  The  data  consist  of
              independent  x-values  and  the outcome 0 or 1 for each of the x-values. The result can be used to
              estimate the probability that a certain x-value gives 1.

              list xdata
                     List of values for which the success (1) or failure (0) is known

              list ydata
                     List of successes or failures corresponding to each value in xdata.

       ::math::statistics::logistic-probabilitycoeffsx
              Calculate the probability of success for the value x given the coefficients of the logistic model.

              list coeffs
                     List of coefficients as determine by the logistic-model command

              float x
                     X-value for which the probability needs to be determined

Keywords

       data analysis, mathematics, statistics

Multivariate Linear Regression

       Besides the linear regression with a single independent variable, the  statistics  package  provides  two
       procedures for doing ordinary least squares (OLS) and weighted least squares (WLS) linear regression with
       several variables. They were written by Eric Kemp-Benedict.

       In  addition  to  these two, it provides a procedure (tstat) for calculating the value of the t-statistic
       for the specified number of degrees of  freedom  that  is  required  to  demonstrate  a  given  level  of
       significance.

       Note: These procedures depend on the math::linearalgebra package.

       Descriptionoftheprocedures::math::statistics::tstatdof ?alpha?
              Returns the value of the t-distribution t* satisfying

                  P(t*)  =  1 - alpha/2
                  P(-t*) =  alpha/2

              for the number of degrees of freedom dof.

              Given a sample of normally-distributed data x, with an estimate xbar for the mean and sbar for the
              standard  deviation,  the alpha confidence interval for the estimate of the mean can be calculated
              as

                    ( xbar - t* sbar , xbar + t* sbar)

              The return values from this procedure can be compared to an  estimated  t-statistic  to  determine
              whether  the  estimated  value  of  a  parameter is significantly different from zero at the given
              confidence level.

              int dof
                     Number of degrees of freedom

              float alpha
                     Confidence level of the t-distribution. Defaults to 0.05.

       ::math::statistics::mv-wlsweights_and_values
              Carries out a weighted least squares linear regression for the data points provided, with  weights
              assigned to each point.

              The linear model is of the form

                  y = b0 + b1 * x1 + b2 * x2 ... + bN * xN + error

              and each point satisfies

                  yi = b0 + b1 * xi1 + b2 * xi2 + ... + bN * xiN + Residual_i

       The procedure returns a list with the following elements:

              •      The r-squared statistic

              •      The adjusted r-squared statistic

              •      A  list containing the estimated coefficients b1, ... bN, b0 (The constant b0 comes last in
                     the list.)

              •      A list containing the standard errors of the coefficients

              •      A list containing the 95% confidence bounds of the coefficients, with each  set  of  bounds
                     returned as a list with two values

              Arguments:

              list weights_and_values
                     A  list  consisting  of:  the  weight  for  the  first  observation, the data for the first
                     observation (as a sublist), the weight for the second observation (as a sublist) and so on.
                     The sublists of data are organised as lists of the value of the dependent  variable  y  and
                     the independent variables x1, x2 to xN.

              Exampleoftheuse: The weight factors are quite simple: 0.2 for negative values to indicate we
              put less trust in these observations and 1.0 for all positive values.

              # Store the value of the unicode value for the "+/-" character
              set pm "\u00B1"

              # Provide some data
              set data { 0.2 {  -.67  14.18  60.03 -7.5  }
                         1.0 { 36.97  15.52  34.24 14.61 }
                         0.2 {-29.57  21.85  83.36 -7.   }
                         0.2 {-16.9   11.79  51.67 -6.56 }
                         1.0 { 14.09  16.24  36.97 -12.84}
                         1.0 { 31.52  20.93  45.99 -25.4 }
                         1.0 { 24.05  20.69  50.27  17.27}
                         1.0 { 22.23  16.91  45.07  -4.3 }
                         1.0 { 40.79  20.49  38.92  -.73 }
                         0.2 {-10.35  17.24  58.77  18.78}}

              # Call the ols routine
              set results [::math::statistics::mv-ols $data]

              # Pretty-print the results
              puts "R-squared: [lindex $results 0]"
              puts "Adj R-squared: [lindex $results 1]"
              puts "Coefficients $pm s.e. -- \[95% confidence interval\]:"
              foreach val [lindex $results 2] se [lindex $results 3] bounds [lindex $results 4] {
                  set lb [lindex $bounds 0]
                  set ub [lindex $bounds 1]
                  puts "   $val $pm $se -- \[$lb to $ub\]"
              }

       ::math::statistics::mv-olsvalues
              Carries out an ordinary least squares linear regression for the data points provided.

              This procedure simply calls ::mvlinreg::wls with the weights set to  1.0,  and  returns  the  same
              information.

       Exampleoftheuse:

              # Store the value of the unicode value for the "+/-" character
              set pm "\u00B1"

              # Provide some data
              set data {{  -.67  14.18  60.03 -7.5  }
                        { 36.97  15.52  34.24 14.61 }
                        {-29.57  21.85  83.36 -7.   }
                        {-16.9   11.79  51.67 -6.56 }
                        { 14.09  16.24  36.97 -12.84}
                        { 31.52  20.93  45.99 -25.4 }
                        { 24.05  20.69  50.27  17.27}
                        { 22.23  16.91  45.07  -4.3 }
                        { 40.79  20.49  38.92  -.73 }
                        {-10.35  17.24  58.77  18.78}}

              # Call the ols routine
              set results [::math::statistics::mv-ols $data]

              # Pretty-print the results
              puts "R-squared: [lindex $results 0]"
              puts "Adj R-squared: [lindex $results 1]"
              puts "Coefficients $pm s.e. -- \[95% confidence interval\]:"
              foreach val [lindex $results 2] se [lindex $results 3] bounds [lindex $results 4] {
                  set lb [lindex $bounds 0]
                  set ub [lindex $bounds 1]
                  puts "   $val $pm $se -- \[$lb to $ub\]"
              }

Name

       math::statistics - Basic statistical functions and procedures

Plot Procedures

       The following simple plotting procedures are available:

       ::math::statistics::plot-scalecanvasxminxmaxyminymax
              Set  the scale for a plot in the given canvas. All plot routines expect this function to be called
              first. There is no automatic scaling provided.

              widget canvas
                     - Canvas widget to use

              float xmin
                     - Minimum x value

              float xmax
                     - Maximum x value

              float ymin
                     - Minimum y value

              float ymax
                     - Maximum y value

       ::math::statistics::plot-xydatacanvasxdataydatatag
              Create a simple XY plot in the given canvas - the data are shown as a collection of dots. The  tag
              can be used to manipulate the appearance.

              widget canvas
                     - Canvas widget to use

              float xdata
                     - Series of independent data

              float ydata
                     - Series of dependent data

              string tag
                     - Tag to give to the plotted data (defaults to xyplot)

       ::math::statistics::plot-xylinecanvasxdataydatatag
              Create  a  simple  XY  plot  in  the  given canvas - the data are shown as a line through the data
              points. The tag can be used to manipulate the appearance.

              widget canvas
                     - Canvas widget to use

              list xdata
                     - Series of independent data

              list ydata
                     - Series of dependent data

              string tag
                     - Tag to give to the plotted data (defaults to xyplot)

       ::math::statistics::plot-tdatacanvastdatatag
              Create a simple XY plot in the given canvas - the data are shown as  a  collection  of  dots.  The
              horizontal  coordinate  is  equal  to the index. The tag can be used to manipulate the appearance.
              This type of presentation is suitable for autocorrelation functions for instance or for inspecting
              the time-dependent behaviour.

              widget canvas
                     - Canvas widget to use

              list tdata
                     - Series of dependent data

              string tag
                     - Tag to give to the plotted data (defaults to xyplot)

       ::math::statistics::plot-tlinecanvastdatatag
              Create a simple XY plot in the given canvas - the data are shown as a line. See plot-tdata for  an
              explanation.

              widget canvas
                     - Canvas widget to use

              list tdata
                     - Series of dependent data

              string tag
                     - Tag to give to the plotted data (defaults to xyplot)

       ::math::statistics::plot-histogramcanvascountslimitstag
              Create a simple histogram in the given canvas

              widget canvas
                     - Canvas widget to use

              list counts
                     - Series of bucket counts

              list limits
                     - Series of upper limits for the buckets

              string tag
                     - Tag to give to the plotted data (defaults to xyplot)

Statistical Distributions

       In  the  literature  a  large  number  of  probability distributions can be found. The statistics package
       supports:

       •      The normal or Gaussian distribution as well as the log-normal distribution

       •      The uniform distribution - equal probability for all data within a given interval

       •      The exponential distribution - useful as a model for certain extreme-value distributions.

       •      The gamma distribution - based on the incomplete Gamma integral

       •      The beta distribution

       •      The chi-square distribution

       •      The student's T distribution

       •      The Poisson distribution

       •      The Pareto distribution

       •      The Gumbel distribution

       •      The Weibull distribution

       •      The Cauchy distribution

       •      The F distribution (only the cumulative density function)

       •      PM - binomial.

       In principle for each distribution one has procedures for:

       •      The probability density (pdf-*)

       •      The cumulative density (cdf-*)

       •      Quantiles for the given distribution (quantiles-*)

       •      Histograms for the given distribution (histogram-*)

       •      List of random values with the given distribution (random-*)

       The following procedures have been implemented:

       ::math::statistics::pdf-normalmeanstdevvalue
              Return the probability of a given value for a normal distribution with  given  mean  and  standard
              deviation.

              float mean
                     - Mean value of the distribution

              float stdev
                     - Standard deviation of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-lognormalmeanstdevvalue
              Return the probability of a given value for a log-normal distribution with given mean and standard
              deviation.

              float mean
                     - Mean value of the distribution

              float stdev
                     - Standard deviation of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-exponentialmeanvalue
              Return the probability of a given value for an exponential distribution with given mean.

              float mean
                     - Mean value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-uniformxminxmaxvalue
              Return the probability of a given value for a uniform distribution with given extremes.

              float xmin
                     - Minimum value of the distribution

              float xmin
                     - Maximum value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-triangularxminxmaxvalue
              Return  the probability of a given value for a triangular distribution with given extremes. If the
              argument min is lower than the argument max, then smaller values have higher probability and  vice
              versa.  In  the  first  case the probability density function is of the form f(x)=2(1-x) and the
              other case it is of the form f(x)=2x.

              float xmin
                     - Minimum value of the distribution

              float xmin
                     - Maximum value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-symmetric-triangularxminxmaxvalue
              Return the probability of a given  value  for  a  symmetric  triangular  distribution  with  given
              extremes.

              float xmin
                     - Minimum value of the distribution

              float xmin
                     - Maximum value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-gammaalphabetavalue
              Return  the  probability  of  a  given  value  for  a Gamma distribution with given shape and rate
              parameters

              float alpha
                     - Shape parameter

              float beta
                     - Rate parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-poissonmuk
              Return the probability of a given number of occurrences in the same interval  (k)  for  a  Poisson
              distribution with given mean (mu)

              float mu
                     - Mean number of occurrences

              int k  - Number of occurences

       ::math::statistics::pdf-chisquaredfvalue
              Return  the  probability  of  a  given  value  for a chi square distribution with given degrees of
              freedom

              float df
                     - Degrees of freedom

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-student-tdfvalue
              Return the probability of a given value for a Student's  t  distribution  with  given  degrees  of
              freedom

              float df
                     - Degrees of freedom

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-gammaabvalue
              Return  the  probability  of  a  given  value  for  a Gamma distribution with given shape and rate
              parameters

              float a
                     - Shape parameter

              float b
                     - Rate parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-betaabvalue
              Return the probability of a given value for a Beta distribution with given shape parameters

              float a
                     - First shape parameter

              float b
                     - Second shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-weibullscaleshapevalue
              Return the probability of a given value for a Weibull distribution  with  given  scale  and  shape
              parameters

              float location
                     - Scale parameter

              float scale
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-gumbellocationscalevalue
              Return  the  probability  of a given value for a Gumbel distribution with given location and shape
              parameters

              float location
                     - Location parameter

              float scale
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-paretoscaleshapevalue
              Return the probability of a given value for a Pareto  distribution  with  given  scale  and  shape
              parameters

              float scale
                     - Scale parameter

              float shape
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-cauchylocationscalevalue
              Return  the  probability  of a given value for a Cauchy distribution with given location and shape
              parameters. Note that the Cauchy distribution has no finite higher-order moments.

              float location
                     - Location parameter

              float scale
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-laplacelocationscalevalue
              Return the probability of a given value for a Laplace distribution with given location  and  shape
              parameters.  The  Laplace  distribution  consists  of two exponential functions, is peaked and has
              heavier tails than the normal distribution.

              float location
                     - Location parameter (mean)

              float scale
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-kumaraswamyabvalue
              Return the probability of a given value for a Kumaraswamy distribution with given parameters a and
              b. The Kumaraswamy distribution  is  related  to  the  Beta  distribution,  but  has  a  tractable
              cumulative distribution function.

              float a
                     - Parameter a

              float b
                     - Parameter b

              float value
                     - Value for which the probability is required

       ::math::statistics::pdf-negative-binomialrpvalue
              Return  the  probability  of  a  given  value for a negative binomial distribution with an allowed
              number of failures and the probability of success.

              int r  - Allowed number of failures (at least 1)

              float p
                     - Probability of success

              int value
                     - Number of successes for which the probability is to be returned

       ::math::statistics::cdf-normalmeanstdevvalue
              Return the cumulative probability of a given value for a normal distribution with given  mean  and
              standard deviation, that is the probability for values up to the given one.

              float mean
                     - Mean value of the distribution

              float stdev
                     - Standard deviation of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-lognormalmeanstdevvalue
              Return  the  cumulative probability of a given value for a log-normal distribution with given mean
              and standard deviation, that is the probability for values up to the given one.

              float mean
                     - Mean value of the distribution

              float stdev
                     - Standard deviation of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-exponentialmeanvalue
              Return the cumulative probability of a given value for  an  exponential  distribution  with  given
              mean.

              float mean
                     - Mean value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-uniformxminxmaxvalue
              Return the cumulative probability of a given value for a uniform distribution with given extremes.

              float xmin
                     - Minimum value of the distribution

              float xmin
                     - Maximum value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-triangularxminxmaxvalue
              Return  the  cumulative  probability  of  a  given  value for a triangular distribution with given
              extremes. If xmin < xmax, then lower values have a higher probability and  vice  versa,  see  also
              pdf-triangular

              float xmin
                     - Minimum value of the distribution

              float xmin
                     - Maximum value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-symmetric-triangularxminxmaxvalue
              Return  the  cumulative  probability of a given value for a symmetric triangular distribution with
              given extremes.

              float xmin
                     - Minimum value of the distribution

              float xmin
                     - Maximum value of the distribution

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-students-tdegreesvalue
              Return the cumulative probability of a given value for  a  Student's  t  distribution  with  given
              number of degrees.

              int degrees
                     - Number of degrees of freedom

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-gammaalphabetavalue
              Return  the  cumulative probability of a given value for a Gamma distribution with given shape and
              rate parameters.

              float alpha
                     - Shape parameter

              float beta
                     - Rate parameter

              float value
                     - Value for which the cumulative probability is required

       ::math::statistics::cdf-poissonmuk
              Return the cumulative probability of a given number of occurrences in the same interval (k) for  a
              Poisson distribution with given mean (mu).

              float mu
                     - Mean number of occurrences

              int k  - Number of occurences

       ::math::statistics::cdf-betaabvalue
              Return  the  cumulative  probability  of  a  given  value for a Beta distribution with given shape
              parameters

              float a
                     - First shape parameter

              float b
                     - Second shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-weibullscaleshapevalue
              Return the cumulative probability of a given value for a Weibull distribution with given scale and
              shape parameters.

              float scale
                     - Scale parameter

              float shape
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-gumbellocationscalevalue
              Return the cumulative probability of a given value for a Gumbel distribution with  given  location
              and scale parameters.

              float location
                     - Location parameter

              float scale
                     - Scale parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-paretoscaleshapevalue
              Return  the cumulative probability of a given value for a Pareto distribution with given scale and
              shape parameters

              float scale
                     - Scale parameter

              float shape
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-cauchylocationscalevalue
              Return the cumulative probability of a given value for a Cauchy distribution with  given  location
              and scale parameters.

              float location
                     - Location parameter

              float scale
                     - Scale parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-Fnf1nf2value
              Return  the cumulative probability of a given value for an F distribution with nf1 and nf2 degrees
              of freedom.

              float nf1
                     - Degrees of freedom for the numerator

              float nf2
                     - Degrees of freedom for the denominator

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-laplacelocationscalevalue
              Return the cumulative probability of a given value for a Laplace distribution with given  location
              and  shape  parameters.  The Laplace distribution consists of two exponential functions, is peaked
              and has heavier tails than the normal distribution.

              float location
                     - Location parameter (mean)

              float scale
                     - Shape parameter

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-kumaraswamyabvalue
              Return the cumulative probability of a given value  for  a  Kumaraswamy  distribution  with  given
              parameters  a  and  b. The Kumaraswamy distribution is related to the Beta distribution, but has a
              tractable cumulative distribution function.

              float a
                     - Parameter a

              float b
                     - Parameter b

              float value
                     - Value for which the probability is required

       ::math::statistics::cdf-negative-binomialrpvalue
              Return the cumulative probability of a given value for a negative binomial  distribution  with  an
              allowed number of failures and the probability of success.

              int r  - Allowed number of failures (at least 1)

              float p
                     - Probability of success

              int value
                     - Greatest number of successes

       ::math::statistics::empirical-distributionvalues
              Return  a  list  of  values  and  their empirical probability. The values are sorted in increasing
              order.  (The implementation follows the description at the corresponding Wikipedia page)

              list values
                     - List of data to be examined

       ::math::statistics::random-normalmeanstdevnumber
              Return a list of "number" random values satisfying a  normal  distribution  with  given  mean  and
              standard deviation.

              float mean
                     - Mean value of the distribution

              float stdev
                     - Standard deviation of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-lognormalmeanstdevnumber
              Return  a  list of "number" random values satisfying a log-normal distribution with given mean and
              standard deviation.

              float mean
                     - Mean value of the distribution

              float stdev
                     - Standard deviation of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-exponentialmeannumber
              Return a list of "number" random values satisfying an exponential distribution with given mean.

              float mean
                     - Mean value of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-uniformxminxmaxnumber
              Return a list of "number" random values satisfying a uniform distribution with given extremes.

              float xmin
                     - Minimum value of the distribution

              float xmax
                     - Maximum value of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-triangularxminxmaxnumber
              Return a list of "number" random values satisfying a triangular distribution with given  extremes.
              If  xmin  <  xmax,  then  lower  values  have  a  higher probability and vice versa (see also pdf-triangular.

              float xmin
                     - Minimum value of the distribution

              float xmax
                     - Maximum value of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-symmetric-triangularxminxmaxnumber
              Return a list of "number" random values satisfying a symmetric triangular distribution with  given
              extremes.

              float xmin
                     - Minimum value of the distribution

              float xmax
                     - Maximum value of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-gammaalphabetanumber
              Return  a list of "number" random values satisfying a Gamma distribution with given shape and rate
              parameters.

              float alpha
                     - Shape parameter

              float beta
                     - Rate parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-poissonmunumber
              Return a list of "number" random values satisfying a Poisson distribution with given mean.

              float mu
                     - Mean of the distribution

              int number
                     - Number of values to be returned

       ::math::statistics::random-chisquaredfnumber
              Return a list of "number" random values satisfying a chi square distribution with given degrees of
              freedom.

              float df
                     - Degrees of freedom

              int number
                     - Number of values to be returned

       ::math::statistics::random-student-tdfnumber
              Return a list of "number" random values satisfying a Student's t distribution with  given  degrees
              of freedom.

              float df
                     - Degrees of freedom

              int number
                     - Number of values to be returned

       ::math::statistics::random-betaabnumber
              Return  a  list  of  "number"  random  values  satisfying  a  Beta  distribution  with given shape
              parameters.

              float a
                     - First shape parameter

              float b
                     - Second shape parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-weibullscaleshapenumber
              Return a list of "number" random values satisfying a Weibull distribution  with  given  scale  and
              shape parameters.

              float scale
                     - Scale parameter

              float shape
                     - Shape parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-gumbellocationscalenumber
              Return  a  list of "number" random values satisfying a Gumbel distribution with given location and
              scale parameters.

              float location
                     - Location parameter

              float scale
                     - Scale parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-paretoscaleshapenumber
              Return a list of "number" random values satisfying a Pareto  distribution  with  given  scale  and
              shape parameters.

              float scale
                     - Scale parameter

              float shape
                     - Shape parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-cauchylocationscalenumber
              Return  a  list of "number" random values satisfying a Cauchy distribution with given location and
              scale parameters.

              float location
                     - Location parameter

              float scale
                     - Scale parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-laplacelocationscalenumber
              Return a list of "number" random values satisfying a Laplace distribution with given location  and
              shape  parameters.  The  Laplace distribution consists of two exponential functions, is peaked and
              has heavier tails than the normal distribution.

              float location
                     - Location parameter (mean)

              float scale
                     - Shape parameter

              int number
                     - Number of values to be returned

       ::math::statistics::random-kumaraswamyabnumber
              Return a list of "number" random values satisying a Kumaraswamy distribution with given parameters
              a and b. The Kumaraswamy distribution is related to the Beta distribution,  but  has  a  tractable
              cumulative distribution function.

              float a
                     - Parameter a

              float b
                     - Parameter b

              int number
                     - Number of values to be returned

       ::math::statistics::random-negative-binomialrpnumber
              Return a list of "number" random values satisying a negative binomial distribution.

              int r  - Allowed number of failures (at least 1)

              float p
                     - Probability of success

              int number
                     - Number of values to be returned

       ::math::statistics::histogram-uniformxminxmaxlimitsnumber
              Return the expected histogram for a uniform distribution.

              float xmin
                     - Minimum value of the distribution

              float xmax
                     - Maximum value of the distribution

              list limits
                     - Upper limits for the buckets in the histogram

              int number
                     - Total number of "observations" in the histogram

       ::math::statistics::incompleteGammaxp ?tol?
              Evaluate the incomplete Gamma integral

                                  1       / x               p-1
                    P(p,x) =  --------   |   dt exp(-t) * t
                              Gamma(p)  / 0

              float x
                     - Value of x (limit of the integral)

              float p
                     - Value of p in the integrand

              float tol
                     - Required tolerance (default: 1.0e-9)

       ::math::statistics::incompleteBetaabx ?tol?
              Evaluate the incomplete Beta integral

              float a
                     - First shape parameter

              float b
                     - Second shape parameter

              float x
                     - Value of x (limit of the integral)

              float tol
                     - Required tolerance (default: 1.0e-9)

       ::math::statistics::estimate-paretovalues
              Estimate  the  parameters  for  the  Pareto  distribution  that comes closest to the given values.
              Returns the estimated scale and shape parameters, as well as the  standard  error  for  the  shape
              parameter.

              list values
                     - List of values, assumed to be distributed according to a Pareto distribution

       ::math::statistics::estimate-exponentialvalues
              Estimate  the  parameter  for the exponential distribution that comes closest to the given values.
              Returns an estimate of the one parameter and of the standard error.

              list values
                     - List of values, assumed to be distributed according to an exponential distribution

       ::math::statistics::estimate-laplacevalues
              Estimate the parameters for the Laplace distribution that  comes  closest  to  the  given  values.
              Returns  an  estimate  of  respectively  the  location  and  scale  parameters,  based  on maximum
              likelihood.

              list values
                     - List of values, assumed to be distributed according to an exponential distribution

       ::math::statistics::estimante-negative-binomialrvalues
              Estimate the probability of success for the negative binomial distribution that comes  closest  to
              the given values.  The allowed number of failures must be given.

              int r  - Allowed number of failures (at least 1)

              int number
                     - List of values, assumed to be distributed according to a negative binomial distribution.

       TO DO: more function descriptions to be added

Synopsis

       package require Tcl8.59

       package require math::statistics1.6.1::math::statistics::meandata::math::statistics::mindata::math::statistics::maxdata::math::statistics::numberdata::math::statistics::stdevdata::math::statistics::vardata::math::statistics::pstdevdata::math::statistics::pvardata::math::statistics::mediandata::math::statistics::basic-statsdata::math::statistics::histogramlimitsvalues ?weights?

       ::math::statistics::histogram-altlimitsvalues ?weights?

       ::math::statistics::corrdata1data2::math::statistics::interval-mean-stdevdataconfidence::math::statistics::t-test-meandataest_meanest_stdevalpha::math::statistics::test-normaldatasignificance::math::statistics::lillieforsFitdata::math::statistics::test-Duckworthlist1list2significance::math::statistics::test-anova-Falphaargs::math::statistics::test-Tukey-rangealphaargs::math::statistics::test-Dunnettalphacontrolargs::math::statistics::quantilesdataconfidence::math::statistics::quantileslimitscountsconfidence::math::statistics::autocorrdata::math::statistics::crosscorrdata1data2::math::statistics::mean-histogram-limitsmeanstdevnumber::math::statistics::minmax-histogram-limitsminmaxnumber::math::statistics::linear-modelxdataydataintercept::math::statistics::linear-residualsxdataydataintercept::math::statistics::test-2x2n11n21n12n22::math::statistics::print-2x2n11n21n12n22::math::statistics::control-xbardata ?nsamples?

       ::math::statistics::control-Rchartdata ?nsamples?

       ::math::statistics::test-xbarcontroldata::math::statistics::test-Rchartcontroldata::math::statistics::test-Kruskal-Wallisconfidenceargs::math::statistics::analyse-Kruskal-Wallisargs::math::statistics::test-Levenegroups::math::statistics::test-Brown-Forsythegroups::math::statistics::group-rankargs::math::statistics::test-Wilcoxonsample_asample_b::math::statistics::spearman-ranksample_asample_b::math::statistics::spearman-rank-extendedsample_asample_b::math::statistics::kernel-densitydata opt -optionvalue ...

       ::math::statistics::bootstrapdatasampleSize ?numberSamples?

       ::math::statistics::wasserstein-distanceprob1prob2::math::statistics::kl-divergenceprob1prob2::math::statistics::logistic-modelxdataydata::math::statistics::logistic-probabilitycoeffsx::math::statistics::tstatdof ?alpha?

       ::math::statistics::mv-wlsweights_and_values::math::statistics::mv-olsvalues::math::statistics::pdf-normalmeanstdevvalue::math::statistics::pdf-lognormalmeanstdevvalue::math::statistics::pdf-exponentialmeanvalue::math::statistics::pdf-uniformxminxmaxvalue::math::statistics::pdf-triangularxminxmaxvalue::math::statistics::pdf-symmetric-triangularxminxmaxvalue::math::statistics::pdf-gammaalphabetavalue::math::statistics::pdf-poissonmuk::math::statistics::pdf-chisquaredfvalue::math::statistics::pdf-student-tdfvalue::math::statistics::pdf-gammaabvalue::math::statistics::pdf-betaabvalue::math::statistics::pdf-weibullscaleshapevalue::math::statistics::pdf-gumbellocationscalevalue::math::statistics::pdf-paretoscaleshapevalue::math::statistics::pdf-cauchylocationscalevalue::math::statistics::pdf-laplacelocationscalevalue::math::statistics::pdf-kumaraswamyabvalue::math::statistics::pdf-negative-binomialrpvalue::math::statistics::cdf-normalmeanstdevvalue::math::statistics::cdf-lognormalmeanstdevvalue::math::statistics::cdf-exponentialmeanvalue::math::statistics::cdf-uniformxminxmaxvalue::math::statistics::cdf-triangularxminxmaxvalue::math::statistics::cdf-symmetric-triangularxminxmaxvalue::math::statistics::cdf-students-tdegreesvalue::math::statistics::cdf-gammaalphabetavalue::math::statistics::cdf-poissonmuk::math::statistics::cdf-betaabvalue::math::statistics::cdf-weibullscaleshapevalue::math::statistics::cdf-gumbellocationscalevalue::math::statistics::cdf-paretoscaleshapevalue::math::statistics::cdf-cauchylocationscalevalue::math::statistics::cdf-Fnf1nf2value::math::statistics::cdf-laplacelocationscalevalue::math::statistics::cdf-kumaraswamyabvalue::math::statistics::cdf-negative-binomialrpvalue::math::statistics::empirical-distributionvalues::math::statistics::random-normalmeanstdevnumber::math::statistics::random-lognormalmeanstdevnumber::math::statistics::random-exponentialmeannumber::math::statistics::random-uniformxminxmaxnumber::math::statistics::random-triangularxminxmaxnumber::math::statistics::random-symmetric-triangularxminxmaxnumber::math::statistics::random-gammaalphabetanumber::math::statistics::random-poissonmunumber::math::statistics::random-chisquaredfnumber::math::statistics::random-student-tdfnumber::math::statistics::random-betaabnumber::math::statistics::random-weibullscaleshapenumber::math::statistics::random-gumbellocationscalenumber::math::statistics::random-paretoscaleshapenumber::math::statistics::random-cauchylocationscalenumber::math::statistics::random-laplacelocationscalenumber::math::statistics::random-kumaraswamyabnumber::math::statistics::random-negative-binomialrpnumber::math::statistics::histogram-uniformxminxmaxlimitsnumber::math::statistics::incompleteGammaxp ?tol?

       ::math::statistics::incompleteBetaabx ?tol?

       ::math::statistics::estimate-paretovalues::math::statistics::estimate-exponentialvalues::math::statistics::estimate-laplacevalues::math::statistics::estimante-negative-binomialrvalues::math::statistics::filtervarnamedataexpression::math::statistics::mapvarnamedataexpression::math::statistics::samplescountvarnamelistexpression::math::statistics::subdivide::math::statistics::plot-scalecanvasxminxmaxyminymax::math::statistics::plot-xydatacanvasxdataydatatag::math::statistics::plot-xylinecanvasxdataydatatag::math::statistics::plot-tdatacanvastdatatag::math::statistics::plot-tlinecanvastdatatag::math::statistics::plot-histogramcanvascountslimitstag

________________________________________________________________________________________________________________

Things To Do

       The following procedures are yet to be implemented:

       •      F-test-stdev

       •      interval-mean-stdev

       •      histogram-normal

       •      histogram-exponential

       •      test-histogram

       •      test-corr

       •      quantiles-*

       •      fourier-coeffs

       •      fourier-residuals

       •      onepar-function-fit

       •      onepar-function-residuals

       •      plot-linear-model

       •      subdivide

See Also