Use the GSS 2014 data on education fromChapter 5("The Normal Distribution"), Exercise 5.

Mean

Standard Deviation

N

Lower class

12.11

2.83

122

Working class

13.01

2.91

541

Middle class

14.99

2.93

475

Upper class

15.44

2.83

34

1. Construct the 95% confidence interval for the mean number of years of education for lower-class and working-class respondents.
2. Construct the 99% confidence interval for the mean number of years of education for lower-class and middle-class respondents.
3. As our confidence in the result increases, how does the size of the confidence interval change? Explain why this is so.