Please answer

You would like to construct a 99% confidence interval to estimate the population mean price of milk (per gallon) in your city. You select a random sample of prices from different stores. The sample has a mean of 3.80 dollars and a standard deviation of 0.30 dollars. (a) What is the best point estimate, based on the sample, to use for the population mean? X dollars (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. (In the table, Z refers to a standard normal distribution, and t refers to a t distribution.) Could use Sampling scenario Z t Unclear either Z or t The sample has size 85, and it is from a non-normally distributed X 5 O O O O population. The sample has size 13, and it is from a normally distributed O O O O population with an unknown standard deviation. The sample has size 105, and it is from a non-normally distributed O O O O population with a known standard deviation of 0.26