How many observations should a time study analyst plan for in an operation that has a standarddeviation of 1.5 minutes per piece if the goal is to estimate the mean time per piece to within .4minute with a confidence of 95.5 percent?

It is calculated that, in order to estimate the true mean amount of money spent on textbooks this semester by U of M students to within $40 with 99% confidence, we need a sample of 100 students. What sample size would be required to estimate the true mean amount of money spent on textbooks to within $10 with 99% confidence?

A marketing specialist wants to estimate the average amount spent by visitors to an online retailer's newly-designed website. From the data in a preliminary study she guesses that the standard deviation of the amount spent is about 14 dollars. Question 1. How large a sample should she take to estimate the mean amount spent to within 5 dollars with 95% confidence? (Round your answer up to the next largest integer).

People were polled on how many books they read the previous year. Initial survey results indicate that s = 14.3 books. Complete parts (a) through (d) below. Click the icon to view a partial table of critical values. GOLDA (a) How many subjects are needed to estimate the mean number of books read the previous year within four books with 90% confidence? This 90% confidence level requires 35 subjects. (Round up to the nearest subject.) (b) How many subjects are needed to estimate the mean number of books read the previous year within two books with 90% confidence? This 90% confidence level requires 139 subjects. (Round up to the nearest subject.) (c) What effect does doubling the re accuracy have on the sample size? OA. Doubling the required accuracy nearly doubles the sample size. B. Doubling the required accuracy nearly halves the sample size. C. Doubling the required accuracy nearly quadruples the sample size. D. Doubling the required accuracy nearly quarters the sample size. (d) How…