A friend comes to you with the following problem: "I provided my boss a cost equation using regression analysis. He was unhappy with the results, and told me to do more work and not return until I had a lower cost estimate for one of the variables - the number of machine-hours. My initial analysis covered the last 36 months. By dropping four months in which the relation between costs and machine-hours was very high, I was able to get a lower cost estimate for machine-hours." Was what your friend did unethical? Explain.