Answer part A and B for full credit. Show your work.

a) A population is normal with a variance of 59. Suppose you wish to estimate the population mean . Find the sample size needed to assure with 68.26 percent confidence that the sample mean will not differ from the population mean by more than 2 units.

A) 15

B) 30

C) 871

D) 19

b) You want to be 95% confident that the sample standard deviation is within 40% of the population standard deviation.

A) 224

B) 12

C) 14

D) 11