PS In Problem 14.1 data regarding voter turnout in fi ve cities were presented. For the sake of convenience, the data for three of the variables are presented again here along with descriptive statistics and zero-order correlations.

City Turnout Unemployment Rate

% Negative Ads A 55 5 60 B 60 8 63 C 65 9 55 D 68 9 53 E 70 10 48 Mean = 63.6 8.2 55.8 s = 5.5 1.7 5.3 Unemployment Rate

% Negative Ads Turnout 0.95 0.87 Unemployment Rate 0.70

a. Compute the partial correlation coeffi cient for the relationship between turnout (Y )

and unemployment (X ) while controlling for the effect of negative advertising (Z ).

What effect does this control variable have on the bivariate relationship? Is the relationship between turnout and unemployment direct? (HINT: Use Formula