please answer these 2 questions question one has part a and b

We want to conduct a hypothesis test of the claim that the population mean score on a nationwide examination in biology is different from 495. So, we choose a random sample of exam scores. The sample has a mean of 500 and a standard deviation of 71. For each of the following sampling scenarios, choose an appropriate test statistic for our hypothesis test on the population mean. Then calculate that statistic. Round your answers to two decimal places. (a) The sample has size 12, and it is from a population with a distribution about which we know very little. C It is unclear which test statistic to use. X 5 ? (b) The sample has size 20, and it is from a normally distributed population with a known standard deviation of 77. c z-I C It is unclear which test statistic to use. According to records, the amount of precipitation in a certain city on a November day has a mean of 0.10 inches, with a standard deviation of 0.05 inches. What is the probability that the mean daily precipitation will be 0.093 inches or less for a random sample of 40 November days (taken over many years)? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places. X 5