A2. Suppose you were interested in studying the effect of a person’s early retirement (at or below age 62 versus at age 65 or later) on indicators of physical and emotional health. What variables...

A2. Suppose you were interested in studying the effect of a person’s early retirement (at or below age 62 versus at age 65 or later) on indicators of physical and emotional health. What variables would you suggest using as covariates to enhance the comparability of the groups?