Refer to the analysis of car buyers in Exercise 46. (a) Suppose the distribution of the ages of the buyers of the Cadillac Escalade is skewed. Does this affect the use of a normal model as the...

Refer to the analysis of car buyers in Exercise 46.

(a) Suppose the distribution of the ages of the buyers of the Cadillac Escalade is skewed. Does this affect the use of a normal model as the sampling distribution? How skewed can the data become without preventing use of the
-test?

(b) The distribution of the ages of these buyers is in fact bimodal, with one group hovering near 30 and the other at 60+. How does this observation affect the test?