The two-sample data described in Question 8.2.2 would be analyzed by testing H0: X = Y, where

The two-sample data described in Question 8.2.2 would be analyzed by testing H0: μX = μY, where μX and μY denote the true average motorcycle-related fatality rates for states having “limited” and “comprehensive” helmet laws, respectively.
(a) Should the t test for H0: μX = μY follow the format of Theorem 9.2.2 or the approximation given in Theorem 9.2.3? Explain.
(b) Is there anything unusual about these data? Explain.