1. Learn to organize and interpret data in frequency tables and stem-and-leaf plots, and line plots.

2. Vocabulary frequency table cumulative frequency stem-and-leaf plot
line plot

3. A frequency table is a way to organize data into categories or groups.
By including a cumulative frequency column in your table, you can keep a running total of the frequencies in each category.

4. Additional Example 1: Organizing and Interpreting Data in a Frequency Table
The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data. How many cities had average high temperature below 59 degrees?
69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2
February Temperatures in 20 Cities
Average Highs
Frequency
Cumulative Frequency
0–19
20–39
40–59
60–79

5. Check It Out: Example 1 60–69 70–79 80–89 90–99
The list shows the grades received on an English exam. Make a cumulative frequency table of the data. How many students received a grade of 79 or below?
85, 84, 77, 65, 99, 90, 80, 85, 95, 72, 60, 66, 94, 86, 79, 87, 68, 95, 71, 96
English Exam Grades
Grades
Frequency
Cumulative Frequency
Step 1: Choose a scale that includes all of the data values. Then separate the scale into equal intervals.
60–69
70–79
80–89
90–99

6. A stem-and-leaf plot can be used to show how often data values occur and how they are distributed. Each leaf on the plot represents the right-hand digit in a data value, and each stem represents left-hand digits.
Stems Leaves
Key: 2|7 means 27

7. Additional Example 2: Organizing and Interpreting Data in a Stem-and-Leaf Plot
The data shows the number of years coached by the top 15 coaches in the all-time NFL coaching victories. Make a stem-and-leaf plot of the data. Then find the number of coaches who coached fewer than 25 years.
33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17

8. Check It Out: Example 2
The list shows the number of times each soccer player can bounce the ball on their knee. How many soccer players can bounce the ball more than 36 times.
55, 60, 33, 30, 23, 45, 28, 41, 62, 29, 35, 40, 43, 37, 68, 30, 61, 27, 38, 41

9. Additional Example 3: Organizing and Interpreting Data in a Line Plot
Make a line plot of the data. How many hours per day did Morgan babysit most often?
Number of Babysitting Hours in July M T W Th F S Su
Wk 1 6 4 5 8 2
Wk 2 7
Wk 3 1
Wk 4 3

10. Additional Example 3 Continued
Make a line plot of the data. How many hours per day did Morgan babysit most often?
Step 1: The data values range from 0 to 8. Draw a number line that includes this range.

11. Check It Out: Additional Example 3
Make a line plot of the data. How many slices of pizza did most people eat?
Number of Slices eaten per Person 2 4 1 5 3 6

12. Lesson Quiz: Part I The data shows the ages of some hospital nurses.
33, 35, 23, 39, 23, 24, 34, 21, 57, 45, 57, 60, 45, 24, 31, 42, 61, 45, 35, 38

13. Lesson Quiz: Part II The data shows the ages of some hospital nurses.
33, 35, 23, 39, 23, 24, 34, 21, 57, 45, 57, 60, 45, 24, 31, 42, 61, 45, 35, 38

14. Lesson Quiz: Part III The data shows the ages of some hospital nurses.
33, 35, 23, 39, 23, 24, 34, 21, 57, 45, 57, 60, 45, 24, 31, 42, 61, 45, 35, 38
3. Make a line plot of the data. What age occurs most often?