The time in seconds that a sample of 79 callers trying to contact an insurance company had to wait was recorded. After introducing new procedures the waiting time for a sample of 61 callers was recorded. The results are presented in the following grouped frequency distribution:
(a) Determine values for the mean and median of the distributions.
(b) Find an approximate value for the standard deviation of each distribution.
(c) Use the figures you obtain for (a) and (b) to compare the two distributions.