10. Recent General Social Surveys asked subjects. "How long have you lived in the city, town or community where you live now? The possible responses were (less than one year. 1. 2,3,4. The responses of 1415 subjects had a inode of "less than one year," a median of 16 years, a mean of 20.3 and a standard deviation of 18.2.

a) Do you think that the population distribution is normal? Why or why not?

b) Based on your answer in (a). is it valid to construct a 99% confidence interval for the truc mean for the population represented by this sample? If not. explain why not If it is valid, do so and interpret.