40. A study investigating the relationships among voting patterns, pohtical opinions, and age takes a random sample of 100 individuals in a typical precinct.

a) If the standard deviation of the ages of all individuals in the precinct is = 15. find the probability that the mean age of the individuals sampled is within 2 years of the mean age for all individuals in the precinct.

b) Would the probability be larger, or smaller, if = 10?