Calculate the smallest sample size required to estimate the population mean under the following specifications:

a. confidence level 95,, s = 16, and e = 4

b. confidence level 90,, s = 23, and e = 0.5

c. confidence level 99,, s = 0.5, and e = 1

d. confidence level 98,, s = 1.5, and e = 0.2

e. confidence level 95,, s = 6, and e = 2