9.2 Let us modify Computer Exercise C8.4 by using voting outcomes in 1990 for incumbents who were elected in 1988. Candidate A was elected in 1988 and was seeking reelection in 1990; voteA90 is Candidate A's share of the two-party vote in 1990. The 1988 voting share of Candidate A is used as a proxy variable for quality of the candidate. All other variables are for the 1990 election. The following equations were estimated, using the data in VOTE2.RAW: REV and voteA90 = 75.71 + .312 prtystrA + 4.93 democA (9.25) (.046) (1.01) - .929 log(expendA) - 1.950 log(expendB) (.684) (.281) n = 186, R = .495, R = .483, voteA90 70.81.282 prtystrA + 4.52 democA (10.01) (.052) .839 log(expendA) (.687) (1.06) 1.846 log(expendB) + .067 voteA88 (.292) n 186, R2 = .499, R = .485. (.053)

(i) Interpret the coefficient on voteA88 and discuss its statistical significance. (ii) Does adding voteA88 have much effect on the other coefficients?