Question

1. A professor keeps tracks of student complaints received each week. The probability distribution for complaints can be represented as the table shown below. The random variable xi represents the number of complaints, and p( xi) is the probability of receiving xi complaints.

xi	0	1	2	3	4	5	6
p(xi)	.1	.1	.15	.15	.15	.2	.15

What is the average number of complaints received per week?

		3.35
		2.83
		4.12
		2.12

Answer 1

x	p(x)	x*p(x)
0	0.1	0
1	0.1	0.1
2	0.15	0.3
3	0.15	0.45
4	0.15	0.6
5	0.2	1
6	0.15	0.9
sum	1	3.35

the average number of complaints received per week is

E(X) =sum(X*P(x)) = 3.35