stats question

4. To compare two variances in the normal case, let X1,X2, ,Xn be i.i.d. (independently and identically distributed) NCX, of) and let Y1, Y2, , Ym be i.i.d. N(,uy, of?) where the X's and the Y's are independent samples. Argue that under H0: 01% = a}? SX 2 2 ~Fn1,m1 Y where 51% (respectively, 5%) denotes the sample variance for the X (respectively, the Y) sample. 2 Construct a confidence interval for the ratio Isl'5. \"Y