Question

Sue Anne owns a medium-sized business. The probability model below describes the number of employees that may call in sick on any given day.

Number of Employees Sick 0 1 2 3 4 P(X = x) 0.05 0.4 0.25 0.2 0.1

What is the standard deviation of the number of employees calling in sick each day?

Answer 1

The Calculation table for mean and variance

No. of Sick Employee (X)	P(X=x)	X. P(X)	X^2.P(X)
0	0.05	0	0
1	0.4	0.4	0.4
2	0.25	0.5	1
3	0.2	0.6	1.8
4	0.1	0.4	1.6
Total	1	1.9	4.8

The Average number of sick employees

The Variance of the number of employees calling in sick each day

Therefore the Standard deviation of the number of employees calling in sick each day

Answer: The standard deviation of the number of employees calling in sick each day is 1.091