A hospital researcher is interested in the number of times the average post-op patient will ring the nurse during an 8-hour shift. The random variable X is likely to assume the values 0, 1, 2, 3, and 4 with probabilities given as follows X 1 2 3 4 Probability 0.14 0.26 0.22 0.25 0.13 a) What is the probability that the number of times the average post-op patient will ring the nurse during an 8-hour shift is at most 3? b) Calculate the expected number of times the average post-op patient will ring the nurse during an 8-hour shift. Calculate the standard deviation of times the average post-op patient will ring the nurse during an 8-hour shift