18. Newsweek magazine (September 19. 1983) reported results of a poll to investigate wheth- er there was a difference between the percentage of women and the percentage of men who approved of the way Ronald Reagan was handling his job as president Of 511 women interviewed, 40% indicated approval. Of 507 men, 49% indicated approval

a) Find a 90% confidence interval for the difference between the proportion of men and the proportion of women who approved of Reagan's performance. What assumption do you make to ase this method?

b) Interpret the interval ohtamed in part (a). Can you conclude that there is a gender gap?