There are 44 students in an elementary statistics class. on the basis of years of experience, the instructor knows that the time needed to grade a randomly chosen first examination paper is a random variable with an expected value of 5 min and a standard deviation of 4 min. (round your answers to four decimal places.) (a) if grading times are independent and the instructor begins grading at 6: 50 p. m. and grades continuously, what is the (approximate) probability that he is through grading before the 11: 00 p. m. tv news begins?