Exhibit 5-10.According to a study by the Centers for Disease Control and Prevention,about 33% of U.S.births are Caesarean deliveries (National Vital Statistics Report,Volume 60,Number 2,November 2011).Suppose seven expectant mothers are randomly selected. Refer to Exhibit 5-10.The expected number of mothers who will not have a Caesarean delivery is ______.
A)1.24
B)2.31
C)3.50
D)4.69

Question

Quizplus · Accepted Answer

The probability of not having a Caesarean delivery is 1 - 0.33 = 0.67. Since there are 7 expectant mothers, the expected number of mothers who will not have a Caesarean delivery is 7 x 0.67 = 4.69, which is closest to option D.