### Applications of Box-and-Whisker Plots

The TI-83 or TI-84 can be used to create a box-and whisker plot. In the following examples, the TI-83 is used. In later Concepts, key strokes using the TI-84 will be presented to you. The five-number summary values can be determined by using the TRACE feature and the left and right arrows of the calculator or by pressing and using 1-Var Stats on the CALC menu. The **TRACE feature** gives the individual values of the five-number summary one at a time.

#### Using Technology to Construct a Box-and-Whisker Plot

The following numbers represent the number of siblings in each family for 15 randomly selected students:

Use technology to construct a box-and-whisker plot to display the data.

A box-and-whisker plot can be created with a TI-83 calculator as shown below:

Note that when creating a box-and-whisker plot with a TI calculator, you don't have to actually sort the data. The calculator will sort the data automatically when creating the box-and-whisker plot.

#### Listing the Five-Number Summary

List the five-number summary values for the data in the previous example .

The five–number summary can be obtained from the calculator in 2 ways.

a. The following results are obtained by simply using the TRACE feature and the left and right arrows:

The values at the bottom of each screen are the five-number summary.

b. The second method involves pressing and using 1-Var Stats on the CALC menu for L1:

#### Constructing Box-and-Whisker Plots

Construct a box-and-whisker plot using technology to represent the average number of sick days used by 9 employees of a large industrial plant. The numbers of sick days are as follows:

What are the values for the five-number summary?

The screens below show the five-number summary:

The values for the five-number summary are as follows:

Min. Value

Med

Max. Value

This can be verified by pressing and using 1-Var Stats on the CALC menu for L1.

### Example

#### Example 1

The following data represents the number of flat-screen televisions assembled at a local electronics company for a sample of 28 days:

Using technology, construct a box-and-whisker plot for the data. What are the values for the five-number summary?

First press and choose Edit on the EDIT menu. Enter the data values into L1, and then press . Press and make sure that your settings are as follows. Note that for Type, the middle graph in the second row is selected.

Now press and make sure that your settings are as shown below:

Finally, press . The following screens show the steps necessary to determine the five-number summary using the TI-83:

The values for the five-number summary are as shown below:

Min. Value

Med

Max. Value

This can be verified by pressing and using 1-Var Stats on the CALC menu for L1.

### Review

For each of the following box-and-whisker plots, determine the five-number summary and give one possible data set that could produce the box-and-whisker plot.

### Review (Answers)

To view the Review answers, open this PDF file and look for section 7.12.