The mean prepartion fee H&R blocked charged retail customers last year was $183 (The wall street Journal, March 7,2012.) Use this price as the population mean and assume the populations standard deviation of prepartion fee is $50.
A) what is the probability that them mean price for a sample of 30 H&R block retail customers is within $8 of the population mean?
B) what is the proability that the mean price for a sample of 50 H&R block retail customers is within $8 of the population mean?
C) what is the proability that the mean price for a sample of 100 H&R block retail customers is within $8 of the population mean?
D) Which if any of the sample sizes in parts a, b, c would you recommend to have at least .95 probability that the sample mean is within $8 of the population mean?