Author Question: The economics department secretary wants to estimate the average number of bottled drinks sold each ... (Read 74 times)

armygirl · **on:** Jun 24, 2018

The economics department secretary wants to estimate the average number of bottled drinks sold each day out of the vending machine. Similar vending machine sales have a standard deviation of 9 bottles per day. He wants to be 95-percent confident that the estimate, x, obtained is within 3 bottles of the true mean . How large a sample is needed if the limit of the Coke machine for one day is 120?

Question 2

As marketing manager for a very large discount building supply, you wish to know what proportion of your city's population conducted do-it-yourself home improvement projects during the past year. The national percentage is 62; therefore, you decide to use this value in estimating sample size for a study to achieve 90 confidence with the estimate no more than 5 from the true proportion. If you know that the total city population is 30,000, what is the appropriate sample size?