9. Chapman et al. (1997) interviewed 68 pregnant inner city women and their male partners twice during their pregnancy, once between three and six months into the pregnancy and again between six and nine months into the pregnancy.

Table 11 shows the correlations among several of their measures. (“Zero-Order Correlations” means the same thing as ordinary correlations.) Most important in this table are the correlations among women’s reports of their own stress, men’s reports of their partners’ stress, women’s perception of their partners’ support at the first and at the second interviews, and women’s depression at the first and at the second interviews.
Explain the results on these measures as if you were writing to a person who has never had a course in statistics. Specifically,

(a) explain what is meant by a correlation coefficient using one of the correlations as an example;

(b) study the table and then comment on the patterns of results in terms of which variables are relatively strongly correlated and which are not very strongly correlated; and

(c) comment on the limitations of making conclusions about the direction of causality based on these data, using a specific correlation as an example (noting at least one plausible alternative causal direction and why that alternative is plausible).