Probability Distribution Functions

(Revised 2011-07-01: Fixed problem with Chi-square for very large chi-square and degrees of freedom. Thank you Heinz-Jurgen!)


This screen computes the probability distribution functions and their inverses for four common statistical distributions.

Note: Before using this page for the first time, make sure you read the JavaStat user interface guidelines for important information about interacting with JavaStat pages.

Normal (Gaussian)

z
p

Note: p is the area in the two tails of the distribution

Student t

t
d.f.
p

Note: p is the area in the two tails of the distribution

Chi Square

ChiSq
d.f.
p

Note: p is a "one-tailed" area (from ChiSq to infinity)

Fisher F

F
d.f.1 (num)
d.f.2 (denom)
p


Note: p is a "one-tailed" area (from F to infinity)

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