To estimate the mean score mu of those who took the Medical College Administration Test on your campus, you will need to obtain the scores of an SRS of students. From published information, you know t

To estimate the mean score mu of those who took the Medical College Administration Test on your campus, you will need to obtain the scores of an SRS of students. From published information, you know that the scores are approximately Normal with a standard deviation of 6.5. You want your sample mean x bar to estimate mu with an error of no more than 1 point in either direction. 

a. What standard deviation must x bar have so that 99.7% of all the samples give an x bar within 1 point of mu? b) How large a SRS do you need in order to reduce the standard deviation of x bar to the value you found in part a