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Let the random variable x represent the number of girls in a family with three c

ID: 3291113 • Letter: L

Question

Let the random variable x represent the number of girls in a family with three children. Assume the probability of a child being a girl is 0.36. The table on the right describes the probability of having x number of girls. Determine whether the table describes a probability distribution. If it does, find the mean and standard deviation. Is it unusual for a family of three children to consist of three girls? A. mu = 1.08 B. The table is not a probability distribution. Find the standard deviation of the random variable. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. sigma = B. The table is not a probability distribution.

Explanation / Answer

Mean = 0*0.262 + 1*0.442 + 2*0.249 + 3*0.047

= 1.08

Variance = (02*0.262 + 12*0.442 + 22*0.249 + 32*0.047) - (1.081)2

= 1.861 - 1.166 = 0.695

Standard deviation = sqrt(variance)

= sqrt (0.695)

= 0.83