(a) What is the mean patient age for those suffering from post-stroke depression and diabetes mellitus?

(b) What is the mean patient age for those suffering from post-stroke depression and are not diabetic?

(c) What is the mean patient age for those free of post-stroke depression and are diabetic?

(d) What is the mean patient age for those free of post-stroke depression and are not diabetic?

(e) Does there appear (by looking at the graph) to be a relationship between age and whether the patient has diabetes and post-stroke depression?

(f) Could the patient’s age be used to improve the prediction if someone has diabetes and post-stroke depression?