Question

2) The ways that we communicate have been dramatically affected by the use of answering machines, fax machines, voice mail, and e-mail. Suppose a sociologist wants to determine the current percentage of U.S. households currently using e-mail. a) Given the fact that in 1997, 16.9% of U.S. households used e-mail, how many households must be surveyed in order to be 95% confident that the current sample percentage is in error by no more than four percentage points? b) Answer the same question if we have no prior 1997 information. 3) When 14 different second-year medical students at Bellevue Hospital in NYC measured the blood pressure of the same person, they obtained the results listed below. Construct a 95% confidence interval estimate of the population standard deviation and write a sentence that interprets this interval. 138 130 130 130 135 144 140 143 120 125 120 140130150

Answer 1

(2)