You would like to construct a 95% confidence interval to estimate the population mean score 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 495 and a standard deviation of 76. (a) What is the best point estimate, based on the sample, to use for the population mean? 5 ? (b) For each of the following sampling scenarios, determine which distribution should be used to calculate the antical value for the 95% confidence interval for the population mean. (In the table, Z refers to a standard normal distribution, and r refers to a tdistritution.) Could use Sampling scenario Unclear either Z or t The sample has size 80, and it is from a non-normally distributed population with a known standard deviation of 78. The sample has size 15. and it is from a population with a distribution about which we know very little. The sample has size 14, and it is from a normally distributed population with an unknown standard deviation. You would like to construct a 95% confidence interval to estimate the population mean score 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 495 and a standard deviation of 76. (a) What is the best point estimate, based on the sample, to use for the population mean? 5 ? (b) For each of the following sampling scenarios, determine which distribution should be used to calculate the antical value for the 95% confidence interval for the population mean. (In the table, Z refers to a standard normal distribution, and r refers to a tdistritution.) Could use Sampling scenario Unclear either Z or t The sample has size 80, and it is from a non-normally distributed population with a known standard deviation of 78. The sample has size 15. and it is from a population with a distribution about which we know very little. The sample has size 14, and it is from a normally distributed population with an unknown standard deviation.