Problem # 6 ( 20 pts) The following frequency distribution table represents the data obtained from a sample of 81 copying machine serviced technicians. The values represent the days between service calls for various copying machines. Approximate the mean and the standard deviation of the frequency following distribution table. Classes Frequency (days) 16 - 18 14 19 - 21 12 22 - 24 18 25 - 27 10 28 - 30 15 31 - 33 6 34 - 36 6 Total