SOLUTION: Suppose that a family has five children, consisting of three girls and two boys. Call the girls Abigail, Brianna, and Courtney; call the boys Duane and Evan. Suppose further that t

Algebra ->  Probability-and-statistics -> SOLUTION: Suppose that a family has five children, consisting of three girls and two boys. Call the girls Abigail, Brianna, and Courtney; call the boys Duane and Evan. Suppose further that t      Log On


   

Question 926820: Suppose that a family has five children, consisting of three girls and two boys. Call the girls Abigail, Brianna, and Courtney; call the boys Duane and Evan. Suppose further that two of these children are to be selected at random.
3. Determine the expected value of the number of girls who will be selected.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

five children: 3G, 2B

Determine the expected value of the number of girls who will be selected

.........

n  P(n)

0  1/10    P(both boys) = %282%2F5%29%281%2F4%29

1  3/5     P(one girl) = %283%2F5%29%282%2F4%29+%2B+%282%2F5%29%283%2F4%29+=+12%2F20

2  3/10    P(two girls) = %283%2F5%29%282%2F4%29+=+6%2F20

    1

......

Exp = 0(1/10) + 1(3/5) + 2(3/10) = 6/10 + 6/10 = 12/10) = 1.2  0r 1 girl