Suppose that you sample two normal populations independently. The variances of these two populations are 21 and 22. You take random samples of sizes n1

Suppose that you sample two normal populations independently. The variances of these two populations are σ21 and σ22. You take random samples of sizes n1 and n2 and observe sample variances of s21 and s22.
a. If n1 = n2 = 21, how large must the fraction s1/s2 be before you can reject the null hypothesis that is no greater than at the 5% significance level?
b. Answer part a when n1 = n2 = 41.
c. If s1 is 25% greater than s2, approximately how large must n1 and n2 be if you are able to reject the null hypothesis in part a at the 5% significance level? Assume that n1 and n2 are equal.