a To create a box-and-whisker plot we need to identify five things.

To find these values first let's rearrange the data from least to greatest.

2 - liter bottles 0.99, 1.15, 1.29, 1.43, 1.79, 1.87, 1.99 12 - packs 2.50, 2.65, 2.99, 3.19, 3.34, 3.89, 4.25

Now we can immediately identify the

minimum

and

maximum

value for the bottles and the cans.

2 - liter bottles Minimum value : 0.99 Maximum value : 1.99 12 - pack Minimum value : 2.50 Maximum value : 4.25

The median is the value that is in the middle of the data set. Since the number of observations is an odd number,

7,

there exists a unique observation that is the

m e d i a n .

2 - liter bottles 0.99, 1.15, 1.29, 1.43, 1.79, 1.87, 1.99 12 - packs 2.50, 2.65, 2.99, 3.19, 3.34, 3.89, 4.25

The

l o w e r

and

u p p e r

quartile is the value that is in the middle of the lower and upper half of the data set. Let's mark these.

2 - liter bottles 0.99, 1.15, 1.29, 1.43, 1.79, 1.87, 1.99 12 - packs 2.50, 2.65, 2.99, 3.19, 3.34, 3.89, 4.25

We can now summarize the information in a table.

Let's use the data in the table to make our double box-and-whisker plot.

Exercise