The Excel F.DIST function calculates the Probability Density Function or the Cumulative Distribution Function for the F Distribution. This function is frequently used used to measure the degree of diversity between two data sets.
The function is new to Excel 2010 and so is not available in earlier versions of Excel.
The syntax of the F.Dist function is:
Where the function arguments are:
x    The (positive) numeric value at which the function is to be evaluated.  
deg_freedom1    An integer specifying the numerator degrees of freedom.  
deg_freedom2    An integer specifying the denominator degrees of freedom.  
cumulative   
A logical argument that specifies the type of F Distribution to be calculated. This can be either:

If either deg_freedom1 or deg_freedom2 are decimal numbers, these are truncated to integers by Excel.
The above chart on the right shows the probability density function for the F Distribution with the numerator degrees of freedom equal to 2 and the denominator degrees of freedom equal to 5.
If you want to use Excel to calculate the value of this function at x = 1, this can be done using the F.Dist function, as follows:
This gives the result 0.308000822.
The above chart on the right shows the Cumulative F Distribution function with the numerator degrees of freedom equal to 2 and the denominator degrees of freedom equal to 5.
If you want to use Excel to calculate the value of this function at x = 1, this can be done using the F.Dist function, as follows:
This gives the result 0.56879885.
For further details and examples of the Excel F.Dist function, see the Microsoft Office website.
If you get an error from the Excel F.Dist function this is likely to be one of the following:
#NUM!   
Occurs if either:

#VALUE!    Occurs if any of the supplied arguments is nonnumeric. 