(1 point) | Question Attempt: 1 of Unlimited Ivan Espanol You would like to construct a 99% confidence interval to estimate the population mean score on a nationwide examination in psychology, and for this purpose we choose a random sample of exam scores. The sample we choose has a mean of 483 and a standard deviation of 78. (a) What is the best point estimate, based on the sample, to use for the population mean? X 5 ? OO (b) For each of the following sampling scenarios, determine which distribution should be used to calculate the critical value for the 99% confidence interval for the population mean. M (In the table, Z refers to a standard normal distribution, and ? refers to a t distribution.) Could use Sampling scenario Z t Unclear either Z or 2 The sample has size 85, and it is from a non-normally distributed O O O O population with a known standard deviation of 77. The sample has size 17, and it is from a population with a O O O distribution about which we know very little. The sample has size 13, and it is from a normally distributed O O O O population with an unknown standard deviation. Save For Later Submit Assignment Recheck Try again