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

	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

• Assuming that years of education is normally distributed in the population, what proportion of working-class respondents have 12 to 16 years of education (2 pts)? What proportion of upper-class respondents have 12 to 16 years of education?