Working Women (June 1999) published the results of a 1999 Gallup poll that found that 92% of adult Americans would vote for a woman president. In 1975, a similar poll found that only 73% would vote for a woman.

a. Let pI9,, and p,,,, represent the population parameters of interest for this study. In the words of the problem, define these parameters.

b. Assume the sample sizes were 2,000 in 1999 and 1,500 in 1975. Are these sample sizes large enough ton conclude that the sampling distribution of

(pls9y - ~~97,) is approximately normally distributed? Justify your answer.

c. Construct a 90% confidence interval for

(P,~~, - pIg7,). Interpret your confidence interval in the context of the problem.

d. Rework part b under the assumption that the sample sizes for 1999 and 1975 are 20 and 50, respectively.