1. The reduction in systolic blood pressure (BP) after a drug for hypertension is administered is one of the key indicators of how well the patient is responding to the drug. The data BP.dta contains the reduction in bold pressure (mm Hg) over a period of four weeks for 20 patients who were randomized to receive the standard drug S or two newer drugs A and B.

Treatment	Drug
1	Standard drug (S)
2	S + a low dose of A (S+AL)
3	S + a high dose of A (S+AH)
4	S + a low dose of B (S+BL)
5	S + a high dose of B (S+BH)

1. Perform a hypothesis test to see if the data support the claim that the treatment A or B has an effect on the BP reduction.
2. Construct a 95% CI for the expected BP reduction for each treatment group.
3. Construct the following four contrasts and test the significance of these contrasts:
   1. Standard drug vs the rest
   2. S+AH vs S+AL
   3. S+BH vs S+BL
   4. A vs B