Question: Determine whether each of these statements is an example of a null hypothesis or an example of an alternative hypothesis.
a. The average weight of Canadian geese is the same as the average weight of Canadian warblers.
b. The proportion of books in the local public library that are novels is higher than the proportion of books in the university library that are novels.
c. The average price of wool jackets in New York City is lower in the summer than in the winter.
d. The proportion of students who receive A grades from Professor Harrington is the same as or higher than the proportion of students who receive A grades from Professor Cantor.