A manufacturing factory for toys has a warrantee of 5 years of engine parts. However, an Engineer believes the engines will malfunction in less than 5 years. He tests a sample of 40 engines and find the average warrantee to be 4.8 years with a standard deviation of 0.50. a. State the null and alternative hypothesis b. Is there enough evidence to support the new warrantee at a 2% significance level