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