3. A doctor collects data on all the men in his practice. Their daily potassium intake is 4500 mglday, with a standard deviation of 1000 mgfdav. They have an average systolic blood pressure of 150 mmHg, with a standard deviation of 10 mmHg. The two variables have correlation r = -0.4. {b} A man is selected at random from the practice. His potassium intake is 5500 mg/dav, which means that he is 8D{s] above the average potassium intake of men in the practice. Another way of expressing his relative potassium intake is that he is at the percentile of intake among all men in the practice. (c) Using regression, we can predict the man from part (b) will have a blood pressure that is 3D{s) (choose between abovefbelow) average. Therefore, he is predicted to be at the percentile of blood pressure