In a random sample of 40 refrigerators, the mean repair cost was $144.00
Question In a random sample of 40 refrigerators, the mean repair cost was $144.00 and the population standard deviation is $18.50. A 90% confidence interval for the population mean repair cost is (139.19,148.81). Change the sample size to n=80. Construct a 90% confidence interval for the population mean repair cost. Which confidence interval is wider? Explain. Construct a […]