The following data represent the annual number of days over 100*F in a city from 195 to 2004. Approximate the mean and standard deviation of annual number of days over 100*F. Treat the data as a population.
# of over 100*F days | 0-9 | 10-19 | 20-29 | 30-39 | 40-49 | 50-59 | 60-69 |
# of years | 32 | 35 | 17 | 10 | 3 | 2 | 1 |