A researcher wants to determine an interval estimate for the average weight of all gorillas (in pounds). She wants to be 95% certain that she is within 5 pounds of the true average. From past studies, it is known that the standard deviation of the weights of gorillas is 11.6 pounds. How many gorillas should she sample to achieve these results?

(a) What is the critical value that corresponds to the given level of confidence? Round to two decimals.

(b) What is the minimum sample size necessary to estimate the population mean? Round to the next integer.