Assume that the family has five children, consisting of three girls and two boys. Call the girls Abigail, Brianna, and Courtney; call the boys Duane and Evan. Assume further that two of these children are to be chosen at random.
1. Mention the sample space of all possible pairs of these five children.
2. Find out the probability that one child of each gender will be selected.
3. Find out the expected value of the number of girls who will be selected.