The unknown population mean number of advertising or solicitation emails a retail customer received per day is 7.

The unknown population mean number of advertising or solicitation emails a retail customer received per day is 7.2. An advertising company wants to estimate the population number of solicitation e-mails a customer received per day.

Which action should the company avoid taking according to the central limit theorem?

a. Include a maximum of ten customers in each sample

b. Use large sample sizes

c. Calculate the mean of the sample averages

d. Perform many samples of customers