Sam Bogart, the owner of the Play-It-Again Stereo Company, offers 1-year warranties on all the stereos his company sells. For the 30 stereos that were serviced under the warranty last year, the average cost to fi x a stereo was $75 and sample standard deviation was $15. Calculate a 95 percent confi dence interval for the true standard deviation of the cost of repair. Sam has decided that unless the true standard deviation is less than $20, he will buy his stereos from a different wholesaler. Help Sam test the appropriate hypotheses, using a signifi cance level of 0.01. Should he switch wholesalers?
Contact us for the solution
