The maker of printer cartridges for laser printers wants to estimate the mean number of documents µ that can be printed on a new high-speed printer. The company decides to test the cartridge on two dozen different laser printers. Each document is identical in number of words and amount of graphics. A histogram of the number of pages printed for each printer shows no outliers and is fairly bell-shaped. The mean and standard deviation of the sample were 3,875 sheets, and 170 sheets, respectively. It can be assumed that the laser printers were a random sample of all laser printers on the market. Which of the following is the correct formula for a 90% confidence interval for the mean number of pages printed with the new type of cartridge?
(A) 3,875 ± 1.711 × (170/v24)
(B) 3,875 ± 1.714 × (170/v24)
(C) 3,875 ± 1.711 × (170/v23)
(D) 3,875 ± 1.714 × (170/v23)
(E) The company should only compute a 95% confidence interval for these data.
Answer: B