Student's t Distribution. The Student's t distribution has density function (for = 1, 2, ...):

f(x) = [(+1)/2] / (/2) * (*)-1/2 *
[1 + (x2/)-(+1)/2

where
     is the degrees of freedom
    (gamma) is the Gamma function
    is the constant Pi (3.14...)


The animation above shows various tail areas (p-values) for a Student's t distribution with 15 degrees of freedom.
statická ukážka



statická ukážka