1. Box-and-Whisker Plots
1-6
Box-and-Whisker Plots
Warm Up
Problem of the Day
Lesson Presentation
Course 2

2. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Warm Up
Use the data below for Questions 1-4.
14, 25, 37, 53, 26, 12, 70, 31
1. What is the mean?
2. What is the median?
3. What is the mode?
4. What is the range?
33.5
28.5
none 58

3. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Problem of the Day
If the sixth-graders checked out 160 books, how many does each symbol in this pictograph represent?
    
   
  
Library Books Checked Out
Sixth Grade
Seventh Grade
Eighth Grade
32 books

4. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Learn to display and analyze data in
box-and-whisker plots.

5. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Vocabulary
box-and-whisker plot
first quartile
second quartile
third quartile
lower extreme
upper extreme

6. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
The table shows the stopping distances of different vehicles from 60 mi/h. A B C D E F G
Vehicle
Stopping Distance (ft)
To show the distribution of the data, you can use a box-and-whisker plot.

7. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
To make a box-and-whisker plot for a set of data, you need to divide the data into four equal parts using quartiles.
The following box-and-whisker plot shows the distribution of the vehicles’ stopping distances.

8. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
first quartile, the median of the lower half of the data set
third quartile, the median of the upper half of the data set
lower extreme, or minimum value
upper extreme, or maximum value
second quartile, the median of the data set

9. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Additional Example 1: Reading a Box-and-Whisker Plot
Use the box-and-whisker plot of students enrolled in craft classes to answer each question.
A. What is the largest class size?
The largest data value is represented by the upper extreme on the box-and whisker plot. This value is 25.
B. What is the range of the class sizes?
The range is the difference between the lower extreme
and the upper extreme
: 25 – 10 = 15.
C. About what fraction of the values are greater than 20?
One of the four parts of the box-and-whisker plot falls above 20. This means about one-fourth of the values are greater than 20.

10. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Try This: Example 1
Use the box-and-whisker plot of the amount of money spent on a pair of shoes to answer each question.
A. What was the highest amount of money spent on a pair of shoes? 41
B. What is the range of shoe prices?
The range is the difference between the lower extreme
and the upper extreme
: 41 – 27 = 14. 1 2
C. What fraction of shoes cost more than $35?

11. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Additional Example 2: Making a Box-and-Whisker Plot
Use the data to make a box-and-whisker plot.
Step 1: Find the lower and upper extremes, the median, and the first and third quartiles.
Order the data from least to greatest. 67 67 69 73 75 75 81 85
Find the lower and upper extremes. 67 69 73 75 81 85 67 69 73 75 81 85 +
Find the median. 2
=74

12. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Additional Example 2 Continued
Find the first and third quartiles. 67 69 73 75 81 85
first quartile =
= 68 2
third quartile =
= 78 2

13. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Additional Example 2 Continued
Step 2: Draw a number line.
Above the number line, plot points representing the lower and upper extremes,
the median,
and the first and third quartiles.
Step 3: Draw a box through the first and third quartiles.
Inside the box, draw a vertical line through the median.
Then draw lines from the first and third quartiles to the extremes. These lines are called whiskers.

14. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Try This: Example 2
Use the data to make a box-and-whisker plot.
Step 1: Find the lower and upper extremes, the median, and the first and third quartiles.
Order the data from least to greatest. 22 24 27 31 35 38 42
Find the lower and upper extremes. 22 24 27 31 35 38 42 22 24 27 31 35 38 42
Find the median.
Find the first and third quartiles. 22 24 27 31 35 38 42

15. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Try This: Example 2 Continued
Step 2: Draw a number line.
Above the number line, plot points representing the lower and upper extremes,
the median,
and the first and third quartiles.
Step 3: Draw a box through the first and third quartiles.
Inside the box, draw a vertical line through the median.
Then draw lines from the first and third quartiles to the extremes. These lines are called whiskers.

16. Box-and-Whisker Plots
Course 2
1-6
Box-and-Whisker Plots
Lesson Quiz
Use the data for Questions 1-3.
24, 20, 18, 25, 22, 32, 30, 29, 35, 30, 28, 24, 38
1. What is the range?
2. What is the 3rd quartile?
3. Create a box-and-whisker plot for the data. 20 31