The test statistic for an F-test is simply the ratio of the square of
the two standard deviations:
-F = s[sub 1][super 2] / s[sub 2][super 2]
+[expression F = s[sub 1][super 2] / s[sub 2][super 2]]
where s[sub 1] is the standard deviation of the first sample and s[sub 2]
is the standard deviation of the second sample. Or in code:
The upper and lower critical values can be computed using the quantile function:
-F[sub (1-alpha; N1-1, N2-1)] = `quantile(fisher_f(N1-1, N2-1), alpha)`
+[expression F[sub (1-alpha; N1-1, N2-1)] = `quantile(fisher_f(N1-1, N2-1), alpha)`]
-F[sub (alpha; N1-1, N2-1)] = `quantile(complement(fisher_f(N1-1, N2-1), alpha))`
+[expression F[sub (alpha; N1-1, N2-1)] = `quantile(complement(fisher_f(N1-1, N2-1), alpha))`]
In our example program we need both upper and lower critical values for alpha
and for alpha/2: