Hypothesis: Mallard ducks grow to a larger size when fed on corn than when fed on rhubarb
Which statement of purpose best defines the objective of an experment to test this hypothesis?
A. To see if mallards will eat corn and rhubarb
B. To determine the rate at which mallards eat corn when it is mixed with rhubarb
C. To measure the average size of mallard ducks
D. To compare the average weight of mallards raised on corn to the average weight of mallards raised on rhubarb