1. Find a confidence interval for assuming that the sample is from a normal population with known population standard deviation.

x = 20, = 3, n = 100, 95 percent confidence

A)(19.405, 20.595)

B)(17.412, 20.588)

C)(19.412, 20.588)

D)(19.412, 21.588)

2. Find a confidence interval for assuming that the sample is from a normal population with unknown population standard deviation.

x = 20, s = 3, n = 100, 95 percent confidence

A)(18.412, 20.588)

B)(17.412, 20.588)

C)(19.412, 20.588)

D)(19.405, 20.595)

My answers are: 1) C and 2) D

Are my answers correct? Why or why not? Please provide explanations.