Statistician: Two major studies found no causal link between medical procedure X and disorder Y, but these studies are flawed. One study looked at 1, 000 people who had undergone procedure X and the other study looked at 1, 100 people who had undergone procedure X. But because disorder Y occurs in only . 02 percent of the population, researchers would need to include many more than 1, 100 people in a study to detect even a doubling of the rate of disorder Y. Which one of the following most accurately expresses the main conclusion of the statistician's argument?
A: Researchers should conduct more-extensive studies of procedure X to determine whether the procedure is causally linked with disorder Y.
B: Contrary to the findings of two major studies, there is reason to think that procedure X causes disorder Y.
C: The two studies cited did not reach a conclusion as to whether disorder Y results from procedure X.
D: Two studies that discovered no causal link between procedure X and disorder Y are unsound.
Choose A, B, C or D as your solution.
D