Four people will enter an automobile showroom, and each will either purchase a car ( P) or not purchase a car ( N).

a Draw a tree diagram depicting the sample space of all possible purchase decisions that could potentially be made by the four people. b List the sample space outcomes that correspond to each of the following events: ( 1) Exactly three people will purchase a car. ( 2) Two or fewer people will purchase a car. ( 3) One or more people will purchase a car. ( 4) All four people will make the same purchase decision.

c Assuming that all sample space outcomes are equally likely, find the probability of each of the events given in part b.