The Fisher-Snédécor distribution (also called the F-distribution) with n1 and n2 degrees of freedom has density function given by for x ≥ 0,
fisher(n1,n2,x) = |
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(The snecedor command is the same as the fisher command.) If you enter
you will get
The cumulative distribution function for the Fisher-Snédécor distribution with n1 and n2 degrees of freedom at a value x is fisher_cdf(n1,n2,x) = snedecor(n1,n2,x) = Prob(X ≤ x); if you enter
you will get
which can be numerically approximated with
which is
The inverse distribution function for the Fisher-Snédécor distribution with n1 and n2 degrees of freedom is computed with fisher_icdf(n1,n2,h); recall that this will return the value x with fisher_cdf(n1,n2,x) = h. If you enter
you will get
The UTPF (the Upper Tail Probability - Fisher-Snédécor distribution) will compute Prob(X > x). If you enter
you will get