Association between marital status and income
Problem: To earn more, get married? Data show that men who are married, and also divorced or widowed men, earn quite a bit more than men the same age who have never been married. This does not mean that a man can raise his income by getting married, because men who have never been married are different from married men in many ways other than marital status.
1. Suggest several lurking variables that might help explain the association between marital status and income.