You would like to construct a 90% confidence interval to estimate today's population mean temperature, so you make a series of measurements (a random sample) throughout the day. The mean of these measurements is 58.5 degrees Fahrenheit, and their standard deviation is 3.1 degrees Fahrenheit. (a) What is the best point estimate, based on the sample, to use for the population mean? X Idegrees EO (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, Z refers to a standard normal distribution, and f refers to a t distribution.) Could use Sampling scenario Z t Unclear either Z or t The sample has size 17, and it is from a normally distributed X 5 O O O O population with an unknown standard deviation. The sample has size 11, and it is from a population with a O O O O distribution about which we know very little. The sample has size 75, and it is from a non-normally distributed O O O O population with a known standard deviation of 3