A Cost Accountant Wishes to Establish the Average Amount $\mu$ ,Spent by Executives Per Day on Travel and Lodging

Short Answer

A cost accountant wishes to establish the average amount, $\mu$ ,spent by executives per day on travel and lodging.The population standard deviation $\text { σ}$
= $29.The accountant wants to be 90-percent confident that the estimate, $\bar { x }$ ,obtained is within $7 of the true mean.How large a sample is needed?