# solution

Suppose a marketing manager was trying to determine how many students had only one e-mail account that they used regularly. The managerâ€™s intention is to market additional Internet services to students who have only one or no e-mail account.

Â a. What is the proportion of students in the sample that have more than one e-mail account?

Â b. If the student population is 5 million students, what sample size is needed to estimate the actual proportion of students with more than one active e-mail account within 61 percent?

c. What sample size is needed to estimate the actual proportion of students with more than one active e-mail account within 65 percent?

Â d. If the decision to launch this marketing activity involves an investment of approximately \$75,000 for this company (with median annual revenues of \$3 million), what level of precision would you recommend?

Q140-:

Suppose the speed limits in thirteen countries in miles per hour are as follows:

What is the mean, median, and mode for these data? Feel free to use your computer (statistical software or spreadsheet) to get the answer. Which is the best measure of central tendency for this data?