A study was performed to determine if there are differences in the effect of placebo, lisinopril or amlodipine on carotid artery blood flow in patients with hypertension. Twelve (10) hypertensive patients were treated with placebo, lisinopril or amlodpine for 7 days each in a double blind, randomized, cross over experimental design (each patient received each drug for 7 days, followed by 7 days with no drug with the order of drug administration randomized). Carotid artery blood flow velocity was measured using Doppler Ultrasound imaging at the end of each treatment period. Resultant data are shown below (values are blood flow velocities in cm/s):

Subject Placebo Lisinopril Amlodipine Row Sum (Row Sum y y)^2 31 49 33 113 4263 37 45 36 118 4672 34 51 34 119 4686 29 39 31 99 3269 37 45 27 GOD VO UA WNA 109 3954 32 52 38 121 4897 36 47 26 109 3937 48 55 33 136 6165 34 40 36 110 4033 10 38 46 30 114 4332 Totals 1148 44207 n 10 10 10 30 Mean 35.56 46.69 32.33 Variance 27.70 25.33 15.44 Sum y 355.55 469.03 323.28 1147.85 (Sum y)^2/ 12641.74 21998.59 10450.68 45091.01 n Sum y^2 11930.37 22226.60 10589.62 45707.23