Although the rules of probability are just basic facts about percents or proportions, we need to be able to use the language of events and their probabilities. Choose an American adult aged 20 years and over at random. Define two events: A= the person chosen is obese
B= the person chosen is overweight, but not obese.

According to the National Center for Health Statistics,
P(A)=0.38
P(B)=0.33

1. Explain why events A and B are disjoint.

a. Because event B rules out obese subjects.
b. Because an obese person is certainly overweight.
c. Because some people may be considered obese and overweight.
d. Because some people are not obese nor overweight.

2. Say in plain language what the event "A or B" is.

a. "A or B" is the event that the person chosen is overweight or obese.
b. "A or B" is the event that the person chosen is overweight and obese.
c. "A or B" is the event that the person chosen is overweight or obese or both.
d. "A or B" is the event that the person chosen is not obese or not over weight.