12.29. Goto the GSS website sda.berkeley.edu/GSS.

(a) Analyze the change over time (GSS variable YEAR)

in the mean of political ideology (POLVIEWS) by political party identification (PARTYID). Compare strongRepublicans to strong Democrats in 1974 and in the latest survey, and summarize the rather dramatic change.

(b) For the latest survey, report the sample mean political ideology for the 2 × 2 cross-classification of RACE

(using black and white) and SEX. For the model E(y) =

α + β1r + β2s, where r = 1 for white and r = 0 for black and s = 1 for male and s = 0 for female, give approximate values (to one decimal place) that you would obtain for αˆ ,

ˆβ

1, and ˆβ2.