9.14 The quality-control manager at a compact fluorescent light bulb (CFL) factory needs to determine whether the mean life of a large shipment of CFLS is equal to 7,500 hours.

The population standard deviation is 1,000 hours. A random sample of 64 CFLS indicates a sample mean life of 7,250 hours. a. At the 0.05 level of significance, is there evidence that the mean life is different from 7,500 hours? b. Compute the p-value and interpret its meaning. c.Construct a 95% confidence interval estimate of the population mean life of the CFLS. d. Compare the results of (a) and