FDistriQuantile
Declaration: 
FDistriQuantile (p: double; df1, df2: integer): double; 
The function FDistriQuantile returns the value of the quantile of the F distribution for a given probability p, and a specified number of degrees of freedom df1 and df2. The parameter p may take any value in the open interval (0,1). The parameters df1, and df2 may take values between 1 and MaxInt. If FDistriQuantile is called using invalid arguments a value of 0.0 is returned.

Hint 1: 
The calculated value is
exact to about 8 significant figures. 
Hint 2: 
The function FDistriQuantile calculates the quantile by using the integral from 0.0 to the F value. This differs from the convention of how the integral of the F distribution is used in many statistical packages, which tabulate the integral between +infinity and the F value. Thus you have to use 1p to get comparable results. For example, in order to calculate the function FINV(p,df1,df2) of Microsofts Excel® you have to use FDistriQuantile(1p,df1,df2). 
