Page 1 of 4
Stem-and-Leaf Plots
BEFORE
Now
WHY?
You organized data using line
plots and frequency tables.
You’ll organize data using
stem-and-leaf plots.
So you can organize scores in
bowling games, as in Ex. 12.
In the Real World
Word Watch
stem-and-leaf plot, p. 653
leaf, p. 653
stem, p. 653
Internet The table lists how long,
in minutes, you were online each
day for the past 21 days. How can
you display the data so you can see
them grouped in an orderly way?
You can use a stem-and-leaf plot
to organize a large set of data.
In a stem-and-leaf plot , each data
value has two parts, a stem and a
leaf. The leaf is the last digit
on the right. The stem is the
remaining digits. For example,
the leaf of the data value 37 is 7.
The stem is 3.
EXAMPLE
tch Out!
Wa
Be sure to
include all of the stems
between the least and the
greatest. In Example 1, 6 is
a stem even though none
of the data values have a 6
in the tens’ place.
1
22
41
MONDAY
15
TUESDAY
WEDNESDAY 28
50
THURSDAY
19
FRIDAY
44
SATURDAY
27
23
35
54
70
40
37
SUNDAY
42
19
29
53
31
31
35
Making a Stem-and-Leaf Plot
To organize the minutes online in the table above, you can make a
stem-and-leaf plot. The numbers range from 15 to 70. So, the least
stem is 1 and the greatest stem is 7.
1 Order the stems
from least to
greatest.
1
2
3
4
5
6
7
Your turn now
2 Write the leaves
next to their
stems.
1
2
3
4
5
6
7
9
2
5
2
4
0
5
7
1
1
3
3 Order the leaves
from least to
greatest.
9
3 9 8
1 7 5
0 4
0
1
2
3
4
5
6
7
This stands
for 53.
5
2
1
0
0
0
9
3
1
1
3
9
7 8 9
5 5 7
2 4
4
Key: 53 53
Make a stem-and-leaf plot of the data.
1. 31, 14, 22, 51, 33, 16, 21, 24, 22, 15, 30, 28, 39
Lesson 13.5
Stem-and-Leaf Plots
653
Page 2 of 4
EXAMPLE
2
Interpreting Stem-and-Leaf Plots
Diners The stem-and-leaf plot shows the ages of people at a diner.
a. What is the range of the ages?
b. Describe the age group with the
most people.
0
1
2
3
4
0
2
0
6
1
5
1
7 9
1 2 2 2 4 9
8
4
Key: 31 31
Solution
a. The youngest person at the diner is
4 years old, because the least data
value is 0 | 4. The oldest person is 34
years old, because the greatest data
value is 3 | 4. The range is
30 years, because 34 4 30.
b. The stem of 1 has more leaves than
any other, so the age group with the
most people is 10–19 years.
EXAMPLE
3
Finding the Mean, Median, and Mode
Use the stem-and-leaf plot.
a. Find the mean.
b. Find the median.
5
6
7
7 7
1 2 7
0 4
Key: 57 5.7
c. Find the mode.
Solution
Make an ordered list of the 7 values in the stem-and-leaf plot.
5.7, 5.7, 6.1, 6.2, 6.7, 7.0, 7.4
5.7 5.7 6.1 6.2 6.7 7.0 7.4
44.8
a. Mean 7 6.4
7
b. The median is 6.2, because the middle value is 6.2.
c. The mode is 5.7, because it occurs the most times.
Your turn now
Use the stem-and-leaf plot in Example 2.
2. Describe the ages of the people at the diner who are not in the most
common age group.
3. Find the mean, median, and mode(s) of the data.
654
Chapter 13
Probability and Statistics
Page 3 of 4
INTERNET
Exercises
eWorkbook Plus
CLASSZONE.COM
More Practice, p. 720
Getting Ready to Practice
1. Vocabulary Identify the stems and the leaves in the
stem-and-leaf plot.
1 2 4 7
2 1 9
3 5 6 8 9
Key: 14 14
Pets The list below shows the weights, in pounds, of pets
owned by students.
25, 7, 8, 10, 13, 22, 10, 15, 12, 13, 9, 40, 15, 21, 14
2. Find the least stem and the greatest stem for the data.
3. Make a stem-and-leaf plot of the data.
4. Which stem has the most leaves? Explain what this means.
Practice and Problem Solving
Make a stem-and-leaf plot of the data.
5. 15, 18, 24, 32, 28, 18, 21, 16, 32, 41, 25, 31, 18, 25
6. 67, 55, 61, 69, 50, 51, 67, 62, 39, 50, 35, 62, 58, 60
7. 15, 38, 9, 33, 16, 7, 5, 35, 30, 35, 55, 49, 41, 52, 51
8. Find the Error Describe and
1
2
4
correct the error in making
the stem-and-leaf plot.
with
Example
1
2
3
Homework
Exercises
5–8
9–11
9–11
Online Resources
CLASSZONE.COM
• More Examples
• eTutorial Plus
5 9
0 2
3 3 7
Key: 43 43
Tennis The stem-and-leaf plot shows the lengths, in minutes,
of mixed doubles finals matches in Wimbledon tennis for a
period of years.
9. Find the mean, median, mode(s),
and range.
10. Which stem has the most leaves?
Explain what this means.
11. Describe the relationship between
the shortest and longest matches
in two different ways.
5
6
7
8
9
10
11
12
Lesson 13.5
9
6
1
5
3
0
1
9
1 3 3 3 5
5
7
Key: 121 121
Stem-and-Leaf Plots
655
Page 4 of 4
Bowling The table shows your bowling scores in several games.
12. Make a stem-and-leaf plot of the
Bowling Scores
scores. Use the key 19 | 6 196.
13. Suppose your goal was to score at
least 230 in 10 of the games. By how
many games did you miss your goal?
181
222
196
210
217
195
199
204
215
190
202
251
222
230
235
Cell Phones In Exercises 14 and 15, use the stem-and-leaf plot.
It shows the weights, in ounces, of 15 cell phones at a store.
14. Find the mean, median, and mode(s).
15. Writing Which number would you
use as the average weight? Explain.
16. Challenge The least value of a data
4
5
6
7
8
0
0
0
1
2
3
4
1
2
6
8 8
9
2
9
Key: 86 8.6
set is 12.3. The greatest value is 90.7.
Is it appropriate to make a stem-and-leaf plot of the data? Explain.
Mixed Review
Graph the integer on a number line. (Lesson 11.1)
17. 6
18. 5
19. 0
20. 2
21. Your score on a cooking contest is 7. All the scores of the 10 contestants
are listed below. What average can you use so you can say that your
score is above average? Explain. (Lesson 13.4)
7, 10, 10, 6, 9, 5, 8, 7, 5, 5
Basic Skills Copy and complete the statement with <, >, or .
22. 35.89 _?_ 35.889
23. 2.162 _?_ 2.1005
24. 6.017 _?_ 6.01700
Test-Taking Practice
INTERNET
State Test Practice
CLASSZONE.COM
25. Multiple Choice Use the stem-and-leaf plot to find the median
of the data.
0
9 9
1
5 5 6 7 9
2
0 0 0 1 2
A. 8
Key: 20 20
B. 18
C. 20
D. 22
26. Short Response Make a stem-and-leaf plot of Gary’s test scores below.
Did Gary get mostly 90s, 80s, or 70s? Explain.
78, 96, 96, 83, 94, 88, 93, 79, 99, 86, 86
656
Chapter 13
Probability and Statistics