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```Distributions(3)      User Contributed Perl Documentation     Distributions(3)

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@gmx.at>

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

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