FHS Chapter 1 1

Display Data

PS.1.AC.4: Apply probability to real-world situations such as weather prediction, game theory, fair division, insurance tables, and

election theory. Students will be able to construct a

box and whiskers plot.

FHS Chapter 1 2

Box-and Whiskers Plots• Another way to display data is with a box-and-

whiskers plot (sometimes called just a box plot). • This shows how data is grouped around the

median of the data. • We put dots on the median, upper and lower

quartiles, the minimum and the maximum.• We draw a box from the upper to the lower

quartile, a line through the median, and lines from the quartiles to the minimum and maximum.

FHS Chapter 1 3

Example: Box-and-Whiskers Plots

• Let’s look at an example: During the first 7 years of Joe Dimaggio’s career, he hit these homeruns: 29, 46, 32, 30, 31, 30, 21.

• The data are: 29, 46, 32, 30, 31, 30, 21.

• Step 1: put the numbers in order from smallest to largest:

21 29 30 30 31 32 46

FHS Chapter 1 4

• Step 2 divide the data into four groups 21 29 30 30 31 32 46• Dots go above the minimum, maximum,

lower and upper quartiles and the median. Make box plot:

| | | | | | | 20 25 30 35 40 45 50

Example: Box-and-Whiskers Plots

Put these numbers in your calculator under L1, and we will learn to make a box plot on your calculator.

FHS Chapter 1 5

Calculator Box PlotsYou can make a box plot using your calculator.1. To turn on the box plot instead of a normal

graph, hit 2nd Y = and then ENTER . 2. Highlight the On and press ENTER . Then use

the right arrow key to go over until is

highlighted and press ENTER .3. Exit from this by hitting 2nd and then MODE.

Then you can access your list by hitting LIST. Enter the numbers 21, 29, 30, 30 31, 32, 46

FHS Chapter 1 6

Calculator Box Plots (cont.)

4. To see your box plot, hit GRAPH .5. You should set your window large enough to

fit your data using the Xmin and Xmax. For this example, make the Xmin = 20 and Xmax = 50. Always make your Ymin = -1 and Ymax = 1.

6. To see the Median, Upper Quartile, Lower Quartile, Minimum and Maximum, use the TRACE key and the right and left arrow keys on the graph.