Question: Students in grades 3 through 8 in New York State am required to take a state mathematics exam. To meet the state's proficiency standards, a student must demonstrate an under-standing of the mathematics expected at his or her grade level. The following data show the number of students tested in the New York City school system for grades 3 through 8 and the number who met and did not meet the proficiency standards on the exam (New York City Department of Education website. January 16, 2010).
a. Develop a joint probability table for these data.
b. What are the marginal probabilities? What do they tell about the probabilities of a student meeting or not meeting the proficiency standards on the exam?
c. If a randomly selected student is a third grader. what is the probability that the student met the proficiency standards? If the student is a fourth grader. what is the probability that the student met the proficiency standards?
d. If a randomly selected student is known to have met the proficiency standards on the exam. what is the probability that the student is a third grader? What is the probability if the student is a fourth grader?