Statistics::Distributions - phpMan

NAME
    Statistics::Distributions - Perl module for calculating critical values
    and upper probabilities of common statistical distributions

SYNOPSIS
      use Statistics::Distributions;

      $chis=Statistics::Distributions::chisqrdistr (2,.05);
      print "Chi-squared-crit (2 degrees of freedom, 95th percentile "
           ."= 0.05 level) = $chis\n";

      $u=Statistics::Distributions::udistr (.05);
      print "u-crit (95th percentile = 0.05 level) = $u\n";

      $t=Statistics::Distributions::tdistr (1,.005);
      print "t-crit (1 degree of freedom, 99.5th percentile = 0.005 level) "
           ."= $t\n";

      $f=Statistics::Distributions::fdistr (1,3,.01);
      print "F-crit (1 degree of freedom in numerator, 3 degrees of freedom "
           ."in denominator, 99th percentile = 0.01 level) = $f\n";

      $uprob=Statistics::Distributions::uprob (-0.85);
      print "upper probability of the u distribution (u = -0.85): Q(u) "
           ."= 1-G(u) = $uprob\n";

      $chisprob=Statistics::Distributions::chisqrprob (3,6.25);
      print "upper probability of the chi-square distribution (3 degrees "
           ."of freedom, chi-squared = 6.25): Q = 1-G = $chisprob\n";

      $tprob=Statistics::Distributions::tprob (3,6.251);
      print "upper probability of the t distribution (3 degrees of "
           ."freedom, t = 6.251): Q = 1-G = $tprob\n";

      $fprob=Statistics::Distributions::fprob (3,5,.625);
      print "upper probability of the F distribution (3 degrees of freedom "
           ."in numerator, 5 degrees of freedom in denominator, F = 6.25): "
           ."Q = 1-G = $fprob\n";

DESCRIPTION
    This Perl module calculates percentage points (5 significant digits) of
    the u (standard normal) distribution, the student's t distribution, the
    chi-square distribution and the F distribution. It can also calculate
    the upper probability (5 significant digits) of the u (standard normal),
    the chi-square, the t and the F distribution. These critical values are
    needed to perform statistical tests, like the u test, the t test, the F
    test and the chi-squared test, and to calculate confidence intervals.

    If you are interested in more precise algorithms you could look at:
    StatLib: http://lib.stat.cmu.edu/apstat/ ; Applied Statistics Algorithms
    by Griffiths, P. and Hill, I.D., Ellis Horwood: Chichester (1985)

BUGS
    This final version 1.02 has been released after more than one year
    without a bug report on the previous version 0.07. Nevertheless, if you
    find any bugs or oddities, please do inform the author.

INSTALLATION
    See perlmodinstall for information and options on installing Perl
    modules.

AVAILABILITY
    The latest version of this module is available from the Distribution
    Perl Archive Network (CPAN). Please visit http://www.cpan.org/ to find a
    CPAN site near you or see http://www.cpan.org/authors/id/M/MI/MIKEK/ .

AUTHOR
    Michael Kospach <mike.perl AT gmx.at>

    Nice formating, simplification and bug repair by Matthias Trautner
    Kromann <mtk AT id.dk>

COPYRIGHT
    Copyright 2003 Michael Kospach. All rights reserved.

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

SEE ALSO
    Statistics::ChiSquare, Statistics::Table::t, Statistics::Table::F,
    perl(1).