b). Find the probability that a randomly selected physics student spends at least 5 years doing post-graduate research.c). If a physics student is selected at random, what is the expected number of years that he/she will spend doing post-graduate research?

A physics professor wants to know how many years physics majors spend doing post-graduate research. Using data from past students at his university, he obtains the following probability distribution, where X be the number of years doing post-graduate research. X P(X) 1 0.10 2 0.05 3 0.10 A U 0.30 6 0.20 7 0.10 Use this to fill in the blank and answer the following questions. Give answers to two decimal places accuracy. a) Find the probability that a randomly selected physics student spends exactly 4 years doing post-graduate research