The manager at a local grocery store thinks customers might benefit from a self-checkout aisle because the variation in customer wait times at checkout is high enough to warrant providing alternative checkout options for customers with fewer needs. To aid thedecision, the manager decides to analyze the standard deviation of the wait times for a random sample of customers.

A sample of30

random customers had their wait times recorded. The wait times in minutes for one of these samples can be found in the table below.

Sample of 30 grocery store customers:

11.2

7.2

6

5.8

3.8

30.2

2.8

4.4

10

5.6

12.7

5.2

15

11.6

18.2

29.8

10.4

8.6

4.4

1.8

1.6

4.4

5.2

27.6

12.8

3.6

7.4

5.2

22.8

1.4

Standard deviation?

Variance?