Snedecor's F Distribution Function

JavaScript 
      Enter F Distribution Function Arguments

          x-value: 
     Numerator df: 
   Denominator df:

F Probability :
The F-distribution with f1 and f2 degrees of freedom
is defined to be the distribution of the ratio F = (X1/f1)/(X2/f2),
where X1 and X2 are independent chi-square random variables
with f1 and f2 degrees of freedom respectively.

For example, F(1,2,2)=.5