According to government data, the probability that a woman between the ages of 25 and 29 was never married is 40%. In a random survey of 10 women in this age group, what is the mean and standard deviation of the
Number that never married?
A)mean: 4; standard deviation: 1.55
B)mean: 6; standard deviation: 1.55
C)mean: 6; standard deviation: 155
D)mean: 4; standard deviation: 2.4

Question

Quizplus · Accepted Answer

The mean of the number that never married is calculated as the product of the total number of women surveyed and the probability of a woman never being married, which is $10 \times 0.40 = 4$. The standard deviation is calculated using the formula for the standard deviation of a binomial distribution, $\sqrt{n \times p \times (1-p)}$, which gives $\sqrt{10 \times 0.40 \times (1-0.40)} = \sqrt{10 \times 0.40 \times 0.60} = \sqrt{2.4} = 1.55$.

According to Government Data, the Probability That a Woman Between