State the null and alternative hypotheses for each of the following:
a. You want to show an increase in buying and selling of single-family homes this year when compared with last year's rate.
b. You are testing a new recipe for "low-fat" cheesecake and expect to find that its taste is not as good as traditional cheesecake.
c. You are trying to show that music lessons have a positive effect on a child's self-esteem.
d. You are investigating the relationship beween a person's gender and the automobile he or she drives-specifically you want to show that more males than females drive truck-type vehicles.