# Question: Jack s Auto Insurance Company customers sometimes have to wait a

Jack’s Auto Insurance Company customers sometimes have to wait a long time to speak to a customer service representative when they call regarding disputed claims. A random sample of 25 such calls yielded a mean waiting time of 22 minutes with a standard deviation of 6 minutes. Construct a 99% confidence interval for the population mean of such waiting times. Assume that such waiting times for the population follow a normal distribution.

## Answer to relevant Questions

A random sample of 36 mid-sized cars tested for fuel consumption gave a mean of 26.4 miles per gallon with a standard deviation of 2.3 miles per gallon. a. Find a 99% confidence interval for the population mean, µ. b. ...A dentist wants to find the average time taken by one of her hygienists to take X-rays and clean teeth for patients. She recorded the time to serve 24 randomly selected patients by this hygienist. The data (in minutes) are ...Check if the sample size is large enough to use the normal distribution to make a confidence interval for p for each of the following cases. a. n = 50 and p̂ = .25 b. n = 160 and p̂ = .03 c. n = 400 and p̂ = .65 d. n = 75 ...a. How large a sample should be selected so that the margin of error of estimate for a 99% confidence interval for p is .035 when the value of the sample proportion obtained from a preliminary sample is .29? b. Find the most ...A mail-order company promises its customers that the products ordered will be mailed within 72 hours after an order is placed. The quality control department at the company checks from time to time to see if this promise is ...Post your question