Question 1 Not yet answered Marked out of 12.00 Flag question Past studies have shown that juniors taking a particular probability course receive grades according to a normal distribution with mean 65 and variance 36. Seniors taking the same course receive grades normally distributed with a mean of 70 and a variance of 36. A probability class is composed of 75 juniors and 25 seniors. (a) What is the probability that a student chosen at random from the class will receive a grade in the 60's (i.e., between 60 and 70)? (b) If a student is chosen at random from the class, what is the student's expected grade? (c) A student is chosen at random from the class and you are told that the student has a grade in the 60's. What is the probability that the student is a junior?