how to test for equal population variance. In the same setting, perform a two- sided test on Ho: -20%=0. Derive the test statistic, define the critical value you need, and specify the rejection rules. [Hint: (1) F=F(d.da) where U and U have y distributions with d, and d degrees of freedom respectively, and U and U are independent. (2) Cochran's Theorem: (-1~x(n-1).]