describe Expected value and variance and standard deviation.
A volunteer ambulance service handles 0 to 5 service calls on any given day. The likelihood distribution for the number of service calls is as follows
Number of Service Calls

Probability

Number of service calls

Probability

0

0.1

3

0.2

1

0.15

4

0.15

2

0.3

5

0.1

a) describe what is the expected number of service calls?
b) describe what is the variance in the number of service calls? What is the standard deviation?