Suppose that we wish to study the effect of the stimulant digitalis on the blood pressure Y of rats over a dosage range of x = 2 to x = 5 units. The response is expected to be linear over the region; that is, Y = β0 + β1x + ε. Six rats are available for the experiment, and each rat can receive only one dose. What dosages of digitalis should be employed in the experiment, and how many rats should be run at each dosage to maximize the quantity of information in the experiment relative to the slope β1?