1. Anger and heart disease. A nonexperimental study looked at whether people who angered easily were more likely to develop coronary heart disease than those who angered less easily. Spielberger anger scale scores were classified into low, moderate, and high categories. Individuals were followed for up to 72 months (median follow-up time: 53 months). Table 18.9 shows cross-tabulated results for acute and fatal coronary new cases. How you they analyzed this data to answer their research question (provide details and show your work). Use Low category as reference. Use 4 digits decimal and round to the nearest 2 decimals at the end. (10 points)

TABLE 18.9 Data for Exercises 18.4 and 18.10. Coronary heart disease (CHD) incidents according to anger-trait category.

Anger-level CHD+ CHD- Total Low 31 3079 3110 Moderate 63 4668 4731 High 18 615 633 Total 112 8362 8474