Question

Find the indicated probability by using the complementation rule. A percentage distribution is given below for the size of families in one U.S. city. Size Percentage 2 39.9 3 24.4 4 20.1 5 10.8 6 3.3 7 1.5 A family is selected at random. Find the probability that the size of the family is 4 or more. Round results to three decimal places.

a. 0.156
b. 0.844
c. 0.357
d. 0.201

Answer 1

The correct option is c.

Explanation:

The percentage probability distribution is:

Size (X) Percentage

2 39.9

3 24.4

4 20.1

5 10.8

6 3.3

7 1.5

Total 100.0

Compute the probability that the size of the family is 4 or more as follows:

P (X ≥ 4) = P (X = 4) + P (X = 5) + P (X = 6) + P (X = 7)

= 0.201 + 0.108 + 0.033 + 0.015

= 0.357

Thus, the probability that the size of the family is 4 or more is 0.357.

The correct option is c.