Identify whether each of the following statements is more appropriate as a null hypothesis or an alternative hypothesis.

a. Hypothesis: The number of hours that grade-school children spend doing homework predicts their future success on standardized tests.

b. Hypothesis: King cheetahs on average run the same speed as standard spotted cheetahs.

c. Hypothesis: The mean length of African elephant tusks has changed over the last 100 years.

d. Hypothesis: The risk of facial clefts is equal for babies born to mothers who take folic acid supplements compared with those born to mothers who do not.

e. Hypothesis: Caffeine intake during pregnancy affects mean birth weight.