explain in detail

The probability distribution of the number of call-outs made by an ambulance driver during a single shift is given by Number of call-outs 0 1 2 3 4 5 Probability 0.1 0.2 0.25 0.3 0.1 0.05 (a) Find the probability that on a randomly selected shift the driver performs 4 or more call-outs. [3] (b) Show that the mean number of call-outs in a shift is 2.25. [4] (c) Find the probability that in a given shift the number of call-outs is less than the mean number of call-outs. [3]