A hospital researcher is interested in the number of times the average postop 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 U 1 2 3 4 Probabilitv 0.14 0.26 0.22 0.25 0.13 a} What is the probabilityr that the number of times the average post-op patient will ring the nurse during an 8-hour shift is at most 3? PD: 3 3} = 0.8? b} Calculate the expected number oftimes the average post-op patient will ring the nurse during an 8hour shift. = 1.9? (3] Calculate the standard deviation of times the average postop patient will ring the nurse during an 8hour shift