What percentage of the retail transactions studied were cash transactions? Does increasing the extra change to five dollars have an effect on people's behavior? Did those who received an extra dollar count their change? Did the people who returned the extra dollar suspect that it was given to them intentionally?
In a study of honesty conducted in various retail stores, customers who paid in cash and received change were given an extra dollar with their change. Few people who received an extra dollar returned it. So, among those who received an extra dollar, most behaved dishonestly.
The answer to which one of the following questions would most help in evaluating the argument?