A researcher wished to assess the relationship between a manager's level of risk aversion and the manager's age and management level (lower vs. middle vs. upper). Based on sample data on 85 managers, the researcher obtained the sample regression equation est(RiskAversion) = 2 + .3Age + 15Lower - 5Middle where: Lower = 1 if the manager was a lower-level one, 0 otherwise; and Middle = 1 if the manager was a middle manager, O otherwise. The interpretation of -5, the coefficient of Middle, is that, holding Age constant: O the mean risk aversion level of middle managers is 5 units lower than that of managers who are not middle managers. O the mean risk aversion level of middle managers is 5 units lower than that of lower-level managers O the mean risk aversion level of middle managers is 5 units lower than that of upper-level managers as the number of middle managers increases by 1, the risk aversion level decreases on average by 5 units