According to a report done by S & J Power, the mean lifetime of the light bulbs it manufactures is 43 months. A researcher for a consumer advocate group tests this by selecting 14 bulbs at random. For the bulbs in the sample, the mean lifetime is 39 months. It is known that the population standard deviation of the lifetimes is 5 months. Assume that the population is normally distributed. Can we conclude, at the 0.01 level of significance, that the population mean lifetime, M, of light bulbs made by this manufacturer differs from 43 months? Perform a two-tailed test. Then complete the parts below