Returns the inverse of the F probability distribution. If p = FDIST(x,...), then FINV(p,...) = x.
The F distribution can be used in an Ftest that compares the degree of variability in two data sets. For example, you can analyze income distributions in the United States and Canada to determine whether the two countries have a similar degree of diversity.
Syntax
FINV(probability,degrees_freedom1,degrees_freedom2)
Probability is a probability associated with the F cumulative distribution.
Degrees_freedom1 is the numerator degrees of freedom.
Degrees_freedom2 is the denominator degrees of freedom.
Remarks

If any argument is nonnumeric, FINV returns the #VALUE! error value.

If probability < 0 or probability > 1, FINV returns the #NUM! error value.

If degrees_freedom1 or degrees_freedom2 is not an integer, it is truncated.

If degrees_freedom1 < 1 or degrees_freedom1 ≥ 10^10, FINV returns the #NUM! error value.

If degrees_freedom2 < 1 or degrees_freedom2 ≥ 10^10, FINV returns the #NUM! error value.
FINV can be used to return critical values from the F distribution. For example, the output of an ANOVA calculation often includes data for the F statistic, F probability, and F critical value at the 0.05 significance level. To return the critical value of F, use the significance level as the probability argument to FINV.
FINV uses an iterative technique for calculating the function. Given a probability value, FINV iterates until the result is accurate to within ± 3x10^7. If FINV does not converge after 100 iterations, the function returns the #N/A error value.
Example
Probability 
Degrees_freedom1 
Degrees_freedom2 
Formula 
Description (Result) 
0.01 
6 
4 
=FINV([Probability],[Degrees1],[Degrees2]) 
Inverse of the F probability distribution for the specified arguments (15.20675) 