45. If X1, . . . , Xn is a sample from a normal population having known mean μ1 and unknown variance σ2 1 , and Y1, . . . , Ym is an independent sample from a normal population having known mean μ2 and unknown variance σ2 2 , determine a 100(1 − α) percent confidence interval for σ2 1 /σ2 2 .