We want to conduct a hypothesis test of the claim that the population mean score on a nationwide examination in anthropology is different from 323. So, we choose a random sample of exam scores. The sample has a mean of 309 and a standard deviation of 77. 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. (@) The sample has size 10, and it is from a normally distributed population with an unknown standard deviation. O 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 75. It is unclear which test statistic to use