2. A volunteer ambulance service handles 0 to 5 service calls on any given day. The probability distribution for the number of service calls is as follows. Number of Service Calls Probability Number of Probability Service Calls 0 0.10 0.15 0.30 0.20 0.15 0.10 3 4 5 2 a) What is the expected number of service calls? b) What is the variance in the number of service calls? What is the standard deviation