12-2

Box and Whisker Plots

Box and Whisker Plots

Data can be displayed in several ways.

Lists, tables and graphs are just some

of the ways.

Box and whisker plots also display data

in a way that can be very useful to us.

Box and Whisker Plots

Smallest lower median upper maximum

value quartile quartile value

whisker box whisker

Note that quartile sounds like quarter. Each quartile is one

Quarter or one fourth of the data.

Example

Consider these test scores:

50 60 63 71 83 83 85 87 90 98 99

These scores can be shown as a list or

we can display them in a box and

whisker plot.

Example

50 60 63 71 83 83 85 87 90 98 99

First find the median. Median =

Example

50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

Example

50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

Example

50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

The lower quartile is

Example

50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

The lower quartile is 63

Example 50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

The lower quartile is 63

The upper quartile is

Example 50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

The lower quartile is 63

The upper quartile is 90

Example 50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

The lower quartile is 63

The upper quartile is 90

The lowest value is

Example 50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles,

find the median of the upper and lower

portions of the data.

The lower quartile is 63

The upper quartile is 90

The lowest value is 50

Example 50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles, find the median of the upper and lower portions of the data.

The lower quartile is 63

The upper quartile is 90

The lowest value is 50

The maximum value is

Example 50 60 63 71 83 83 85 87 90 98 99

First find the median. Median = 83

To find the upper and lower quartiles, find the median of the upper and lower portions of the data.

The lower quartile is 63

The upper quartile is 90

The lowest value is 50

The maximum value is 99

Box and Whisker Plots

45 50 55 60 65 70 75 80 85 90 95 100

Median = 83

Box and Whisker Plots

45 50 55 60 65 70 75 80 85 90 95 100

Median = 83

Lower quartile = 63 Upper quartile = 90

Box and Whisker Plots

45 50 55 60 65 70 75 80 85 90 95 100

Median = 83

Lower quartile = 63 Upper quartile = 90

Lowest value = 50 Highest value = 99

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median?

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median? 18

What is the lower quartile?

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median? 18

What is the lower quartile? 16

What is the upper quartile?

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median? 18

What is the lower quartile? 16

What is the upper quartile? 21

What is the lowest value?

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median? 18

What is the lower quartile? 16

What is the upper quartile? 21

What is the lowest value? 13

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median? 18

What is the lower quartile? 16

What is the upper quartile? 21

What is the lowest value? 13

What is the highest value?

Try This

12 13 14 15 16 17 18 19 20 21 22 23

What is the median? 18

What is the lower quartile? 16

What is the upper quartile? 21

What is the lowest value? 13

What is the highest value? 22