The State Department of Mental Health is doing a study of the use of drugs to control violent behavior among its patients. The case histories of 75 patients are selected for analysis. For each patient two variables are collected: the number of violent incidents the patient was involved in during the previous 3 months and the daily dosage of Valium given to each patient in milligrams. A regression analysis results in the following:
 = 126.6 - .0138X
sb = .0053 Sy|x = 2.4 r2 = .46
X = 500 sx = 200
What is the department’s hypothesis? Interpret this regression. Is the hypothesis supported? Estimate the number of violent incidents that would be expected if a patient were given 1,000 milligrams of Valium per day. Put a 90% confidence limit around this estimate.