standard_description: Develop a probability distribution for a random variable defined for a sample space in which theoretical probabilities can be calculated; find the expected value. For example, find the theoretical probability distribution for the number of correct answers obtained by guessing on all five questions of a multiple-choice test where each question has four choices, and find the expected grade under various grading schemes.
problem_activity: Solve. Show or explain your work.
a.
$${{2\over3} \times {5\over6}}$$
b.
$${{4\over9} \times { 3\over 8}}$$


aligns: no