You would like to construct a 90% confidence lnlewal to estimate the population mean scote on a nationwide examination in finance, and for this purpose we choose a random sample of exam scores. the sample we choose has a mean of 5H and a standard deviation of 79. (a) What is the best point eatimate, based on the sample, to use for the population mean? [ x .9 (b) For each of the following sampling scenarios, determine which distribution should be used to calculate the critical value for the 90% confidence interval for the population mean. (In the table, 2 refers to a standard normal distribution, and r refers to a r distribution.) Could use V - Unclear Sampling scenario 1 either 2 or r E} . O O 0 population thh an unknown standard deviation. The sample has size 10, and it is from a normally distributed The sample has size 17, and it is from a population with a distribution about which we know very little. The sample has size 100, and it is from a noninormaliv distributed population with a known standard deviation of 77