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 a statistical journal,

P(A) = 0.41and P(B) = 0.33.

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.