A survey asks subjects whether they believe that global warming is happening (yes or no) and how much fuel they plan to use annually for automobile driving in the future, compared to their past use (less, about the same, more).
a. Show the sample space of possible outcomes by drawing a tree diagram that first gives the response on global warming and then the response on fuel use.
b. Let A be the event of a “yes” response on global warming and let B be the event of a “less” response on future fuel use. Suppose P(A and B) 7 P(A)P(B). Indicate whether A and B are independent events, and explain what this means in nontechnical terms.