10. A couple plans to have four children. If we consider only the gender of the children, having 4 children is much like flipping a coin 4 times. There are 16 possible outcomes, and all can be assumed to be equally likely. a. Let the random variable X = the number of girls among 4 children. Use the "Event Tree" approach to list all 16 possible outcomes of having 4 children and write the value of X corresponding to these outcomes for each. Event Tree Outcomes X P [Outcome]