Question

Find the indicated probability.

The table below describes the exercise habits of a group of young adults.

If two different people are randomly selected from the 948 subjects, find the probability that they are both moderate exercisers. Round to six decimal places.

Answer 1

0.007218

Explanation:

Total number of moderate exercisers = 81

We want to find the probability that they are both moderate exercisers

Probability of first person selected is a moderate exercisers = 81/948

After the selection of the first person who must be moderate exercisers,

Now selecting a different person

Thus, discarding the first person, now 947 subjects are left and 80 moderate exercisers are left.

So, Probability of second person selected is a moderate exercisers = 80/947

∴ Probability of 2 different people selected are moderate exercisers = 81/948 × 80/947

= 540/74813

= 0.007218!