4. Friedman and Rosenman (1974) have suggested that personality type is related to heart disease. Specifically, type A people, who are competitive, driven, pressured, and impatient, are more prone to heart disease. On the other hand, type B individuals, who are less competitive and more relaxed, are less likely to have heart disease. Suppose that an investigator would like to examine the relationship between personality type and disease. For a random sample of individuals, personality type is assessed with a standardized test. These individuals are then examined and categorized as to whether they have a heart disorder. The observed frequencies are as follows:

No Heart Heart Disease Disease Type A 32 18 50 Type B 128 22 150 160 40

a. Is there a relationship between personality and disorder? Test at the .05 level of significance.

b. Compute the phi-coefficient to measure the strength of the relationship.