Using R to calculate p-values from F-statistic...

I have an F-ratio and I want to know the corresponding p-values.
I need to know the degrees of freedom for the two values used to calculate the F-ratio.

The function pf() is the one to use.

Here is an example:

pf(161.45, df1=1, df2=1, log.p = TRUE)

so the F ratio is 161.45, df1 and df2 is degrees of freedom for the two values.

Returns: -0.05129291

Here is another example:
pf(2.98, 10, 10, log.p = TRUE)

Returns: -0.05120075

Useful information here too: http://www.r-tutor.com/elementary-statistics/probability-distributions/f-distribution