[T wo-Sample Mean Test when 21 at 22] As an extension to Wednesday' s discussion, what if the two samples have different variance structures. In a large sample problem, we can do the same procedure but with an approximate x2 test. A confidence ellipsoid for pi \"2 is all .111 p2 satisfying 1 1 '1- [X1 '32 (M1 [12)],(11151 + 11252) [X1 "X2 (M1 "M2\" 5 Z1301) Suppose two measurements of power usage for electric car drivers (n1 = 56) and non-electric car drivers (112 = 89).The summary statistics are: X1 [044] '51 = [138.3 238 566 238 731 _ 1300 _ 86.3 196 X2 [3550] '52_[196 560 Find 95% simultaneous confidence intervals for the differences in the mean components and discuss what can be concluded in this test