The 95% confidence interval for the mean duration of imprisonment, μ, of all East German political prisoners with chronic PTSD is between 18.8 months and 48.0 months. (A) Find the sample size required...

The 95% confidence interval for the mean duration of imprisonment, μ, of all East German political prisoners with chronic PTSD is between 18.8 months and 48.0 months.

(A)  Find the sample size required to have a margin of error 12 months and a 99% confidence level.  Assume that σ = 42 months.

(B)  Find the 99% confidence interval for the mean duration of imprisonment, μ, of all East German political prisoners with chronic PTSD if a sample of the size determined in part (a) has a mean of 36.2 months.   Interpret the results.