Problem set 1: Use the following data to answer questions 1-3 (30 points):

Mean

Standard Deviation

N

Lower class

11.63

2.47

169

Working class

12.80

2.85

676

Middle class

14.25

3.08

144

Upper class

15.45

4.05

60

The 2010 GSS provides these statistics above for the average years of education for lower-, working-, middle-, and upper-class respondents and their associated standard deviations.

1.Construct the 90% confidence interval for the mean number of years of education for lower-class and middle-class respondents (10 pts)?