Assume that the class consists of 45 percent freshmen, 20 percent sophomores, 20 percent juniors, and 15 percent seniors. Assume further that 50 percent of the freshmen, 50 percent of the sophomores, 25 percent of the juniors, and 15 percent of the seniors plan to go to medical school. One student is selected at random from the class.
1) What is the probability that the student plans to go to medical school?
2) If the student plans to go to medical school, what is the probability that she is a senior?