Letx be a discrete random variable representing the number of supply orders placed per week by a small business. The probability distribution for this random variable is given in the table below.

Number of supply orders, x	P(x)
0	0.12
1	0.32
2	0.50
3	0.04
4	0.02

Is it considered unusual for this small business to place 3 supply orders in a week?

1. Use the range rule of thumb to answer this question.
2. Then use the rare event rule to answer this question.

Hint: Add some extra columns to the table above and fill them in to help you find the mean () and standard deviation () of the given probability distribution. Below is an illustration of what you need to do to the table to get started. Then you will need to find the sums of two of these additional columns.

Number of supply orders, x	P(x)	x . P(x)	x2	x2 . P(x)
0	0.12
1	0.32
2	0.50
3	0.04
4	0.02