In each of the following instances, determine whether you would use a z- or t-statistic (or neither) to form a 99% confidence interval for m; then look up the appropriate z or t value.

a. Random sample of size n = 17 from a normal distribution with unknown mean m and standard deviation s

b. Random sample of size n = 192 from a normal distribution with unknown mean m and standard deviation s

c. Random sample of size n = 16 from a normal distribution with unknown mean and standard deviation s = 4

d. Random sample of size n = 80 from a distribution about which nothing is known

e. Random sample of size n = 12 from a distribution about which nothing is known