Has the trend of decreasing difference in age at first marriage seen in Exercise 36 gotten stronger recently? The scatterplot and residual plot for the data from 1980 through 2011, along with a regression for just those years, are below.

Dependent variable is Men – Women
R-squared = 49.4% s = 0.225
Variable Coefficient
Intercept ………………… 48.727
Year …………………….. -0.0234
a) Is this linear model appropriate for the post-1980 data? Explain.
b) What does the slope say about marriage ages?
c) Explain why it's not reasonable to interpret the y-intercept.