Hypertension: Researchers examined subjects with hypertension and healthy controls. One of the variables of interest was aortic stiffness index. Measures of this variable were calculated from the aortic diameter evaluated by M-mode echocardiography and blood pressure measured by a sphygmomanometer. Generally, physicians wish to reduce aortic stiffness. In the 15 patients with hypertension (group 1), the mean aortic stiffness index was 19.16 with a standard deviation of 5.29. In the 30 control subjects (group 2), the mean aortic stiffness index was 9.53 with a standard deviation of 2.69. We wish to determine if the two populations represented by these samples differ with respect to mean aortic stiffness. Perform a complete hypothesis test