Mean	Standard Deviation	N
Lower class	11.36	2.96	121
Working class	12.73	2.79	676
Middle class	14.40	3.04	636
Upper class	15.49	2.95	53

The 2008 GSS provides these statistics above for the average years of education for lower-, working-, middle-, and upper-class respondents and their associated standard deviations.

Construct the 95% confidence interval for the mean number of years of education for lower-class and middle-class respondents