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 Espanol sample) throughout the day. The mean of these measurements is 64 degrees Fahrenheit, and their standard deviation is 4 degrees Fahrenheit. (a) What is the best point estimate, based on the sample, to use for the population mean? X degrees ? OD (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 { refers to a t distribution.) M Sampling scenario Could use Z either Z or t Unclear The sample has size 100, and it is from a non-normally X 2 distributed population. O O O O The sample has size 14, and it is from a normally distributed O O O population with an unknown standard deviation. The sample has size 13, and it is from a normally distributed O O O O population with a known standard deviation of 4. Save For Later Submit Assignment Check