Data on suicide rates, age structure, and unemployment rates have been gathered for 100 census tracts. Suicide and unemployment rates have been dichotomized at the median so that each tract could be rated as high or low. Age structure is measured in terms of the percentage of the population age 65 and older. This variable has also been dichotomized, and tracts have been rated as high or low. The following tables display the bivariate relationship between suicide rate and age structure and the same relationship controlling for unemployment.

a. Calculate percentages and gamma for the bivariate table. Describe the bivariate relationship in terms of strength and direction.
SUICIDE RATE BY AGE, CONTROLLING FOR UNEMPLOYMENT A. High Unemployment Population 65 and Older (%)
Low High Totals Low 23 10 33 High 5 12 17 Totals 28 22 50 Suicide Rate Population 65 and Older (%)
Low High Totals Low 22 10 32 High 5 13 18 Totals 27 23 50 Suicide Rate B. Low Unemployment REALITY ORIENTATION BY LENGTH OF INSTITUTIONALIZATION Length of Institutionalization Reality Less Than More Than Orientation five Years five Years Totals Low 200 213 413 High 117 78 195 Totals 317 291 608

b. Calculate percentages and gamma for each partial table. Compare the partial tables with each other and with the bivariate table. Compute partial gamma (Gp).

c. Summarize the results of the control. Does unemployment rate have any effect on the relationship between age and suicide rate? Describe the effect of the control variable in terms of the pattern of percentages, the value of the gammas, and the possible causal relationships among these variables.