You are hired by the government to evaluate the impact of a policy change that affects one group of individuals but not another. Suppose that before the policy change, members of a group affected by the policy averaged 15,543 in earnings, and members of a group unaffected by the policy averaged 15,888. After the policy change,members of the affected group averaged 17,131 in earnings while members of the unaffected group averaged 17,087 in earnings.What is the estimated effect of the policy on individuals' earnings? Your answer should be a numerical number (positive or negative).