Chapter 4.2, Problem 21E

Emergency Room Tests The frequency distribution shows the number of medical tests conducted on 30 randomly selected emergency room patients.

Number of tests performed	Number of patients
0	11
1	9
2	5
3	4
4 or more	1

If a patient is selected at random, find these probabilities:

a. The patient had exactly 3 tests done.

b. The patient had at most 2 tests done.

c. The patient has 1 or 2 tests done.

d. The patient had fewer than 3 tests done.

e. The patient had at least 3 tests done.