Parts A, B, C, D and E

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 7520 hours. The population standard deviation is 1,120 hours. A random sample of 64 light bulbs indicates a sample mean life of 7,296 hours. a. At the 0.05 level of significance, is there evidence that the mean life is different from 7520 hours? b. Compute the p-value and interpret its meaning. c. Construct a 95% confidence interval estimate of the population mean life of the light bulbs. d. Compare the results of (a) and (c). What conclusions do you reach? e. Compare the results of parts (a) through (d) to those when the standard deviation is 800 hours. a. Let be the population mean. Determine the null hypothesis, H0, and the alternative hypothesis, H1. \[ \begin{array}{l} H_{0}: \mu \\ H_{1}: \mu \longdiv { abla } \end{array} \]