2. Describe formallv the following model. Two groups of individuals are sampled at random from a ver'l.r large population. Each member of the second {treatment} group is administered the same dose of a certain drug believed to lower the blood pressure. The blood pressure is measured after 1h. Each member of the rst {control} group is administered an equal doze of a placebo and then has the blood pressure measured after 1h. It is known that the drug either has no effect or lowers the blood pressure, but the distribution of blood pressure in the population sampled before and after administration of the drug is quite unknown