A Gallup poll conducted July 21August 14, 1978, asked 1006 Americans, During the past year, about how

Question:

A Gallup poll conducted July 21–August 14, 1978, asked 1006 Americans, “During the past year, about how many books, either hardcover or paperback, did you read either all or part of the way through? ”Results of the survey indicated that x̄ = 18.8 books and s = 19.8 books.

(a) Construct a 99% conﬁdence interval for the mean number of books Americans read either all or part of during the preceding year. Interpret the interval.

(b) Compare these results to those of Problem 31. Were Americans reading more in 1978?