1. More on con?dence level and interval width. Refer to Exercise 8.19. Would a 99% con?dence interval be wider or narrower than the one that you found in that exercise? Verify your results by computing the interval.

2. Can we use the z test? In each of the following cases state whether or not the Normal approximation to the binomial should be used for a signi?cance test on the population proportion p.

(a) n = 30 and H0: p = 0.2.

(b)  n = 30 and H0: p = 0.6.

(c) n = 100 and H0: p = 0.5.

(d) n = 200 and H0: p = 0.01.