lath1530-N41-WithLab Nicholas Price | 3/10/18 1:3 uiz: Quiz 5 (Over HW 5) Subm i
ID: 3059930 • Letter: L
Question
lath1530-N41-WithLab Nicholas Price | 3/10/18 1:3 uiz: Quiz 5 (Over HW 5) Subm is Question: 1 pt 12 of 16 (7 complete) This Quiz: 16 pts p 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 0.38. The table on the right describes the probability of having x number of girls. Determine whether the table describes a probability1 distribution. If it does, find the mean and standard deviation. Is it unusual for a family of three children to consist of three girls? 0.238 0.269 Find the mean of the random variable. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. Round to two decimal places as needed.) The table is not a probability distribution. O B. 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. Round to two decimal places as needed.) The table is not a probability distribution. B. Click to select your answer searchExplanation / Answer
a) Mean = E(X) = 0 * 0.238 + 1 * 0.438 + 2 * 0.269 + 3 * 0.055 = 1.141 = 1.14
b) E(X2) = 02 * 0.238 + 12 * 0.438 + 22 * 0.269 + 32 * 0.055 = 2.009
Var(X) = E(X2) - (E(X))2 = 2.009 - 1.1412 = 0.7071
Standard deviation = sqrt(0.7071) = 0.84
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