A random sample of n measurements was selected from a population with unkown mean μ and standard deviation σ =20 for each of the situations in parts a through d. Calculate a 99% confidence interval...

A random sample of n measurements was selected from a population with unkown mean
μand standard deviation
σ=20 for each of the situations in parts a through d. Calculate a 99% confidence interval for
μ
for each of these situations.

a. n=50, x̅=25

b. n=250, x̅=103

c. n=100, x̅=13

d. n=100, x̅=4.82