Пакет: libstatistics-distributions-perl (1.02-1)

module for calculating some values of common statistical distributions

Statistics::Distributions 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)