Question: A manager at SmallBell, a small telephone company, wants to determine how long service technicians need to perform a certain repair. In the past, an almost identical repair required 22.75 minutes, with a standard deviation of 0.3 minutes. Compute the sample size of times needing to be collected to ensure that they can be 90 percent confident of correctly estimating the repair time if the manager is willing to tolerate an error rate of 0.04.
- You are asked by the owner of a local hotel chain to develop a customer satisfaction survey to determine the percentage of customers who are dissatisfied with service. In the past year, 20,000 customers were serviced. The owner desires a 95 percent level of confidence with an allowable statistical error of ±0.01. From past estimates, she believes that about 3.5 percent of customers have expressed dissatisfaction. What sample size should you use for this survey?