1-3 Frequency Tables and Stem-and-Leaf Plots

Course 2

Warm Up

Problem of the Day

Lesson Presentation

Warm UpUse these numbers to answer the following questions.

136, 151, 104, 168, 140, 124, 162, 121, 118

1. What is the highest score?

2. What is the lowest score?

3. What is the range of scores?

4. How can you find the median?

168

104

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

64

Arrange the numbers in order and find the value in the middle.

Problem of the Day

Books A, B, C, and D are on the bookshelf. A is between C and B. B is between A and D. D is not on the right. What is the order of the books from right to left? D, B, A, C

Course 2

Frequency Tables and Stem-and-Leaf Plots

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

Vocabulary

frequency tablecumulative frequencystem-and-leaf plot

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data.

69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2

Additional Example 1: Organizing Data in a Frequency Table

February Temperatures in 20 CitiesAverage

HighsFrequency Cumulative

FrequencyStep 1: Look at the range to choose equal intervals for the data.

0–19

20–39

40–59

60–79

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data.

69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2

Additional Example 1 Continued

Step 2: Find the number of data values in each interval. Write these numbers in the “Frequency” column.

February Temperatures in 20 CitiesAverage

HighsFrequency Cumulative

Frequency

0–19

20–39

40–59

60–79

7

5

5

3

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the average high temperatures for 20 cities on one February day. Make a cumulative frequency table of the data.

69, 66, 65, 51, 50, 50, 44, 41, 38, 32, 32, 28, 20, 18, 12, 8, 8, 4, 2, 2

Additional Example 1 Continued

Step 3: Find the cumulative frequency for each row by adding all the frequency values that are above or in that row.

February Temperatures in 20 CitiesAverage

HighsFrequency Cumulative

Frequency

0–19

20–39

40–59

60–79

7

5

5

3

7

12

17

20

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the grades received on an English exam. Make a cumulative frequency table of the data.

85, 84, 77, 65, 99, 90, 80, 85, 95, 72, 60, 66, 94, 86, 79, 87, 68, 95, 71, 96

Try This: Example 1

English Exam GradesGrades Frequency Cumulative

FrequencyStep 1: Look at the range to choose equal intervals for the data.

60–69

70–79

80–89

90–99

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the grades received on an English exam. Make a cumulative frequency table of the data.

85, 84, 77, 65, 99, 90, 80, 85, 95, 72, 60, 66, 94, 86, 79, 87, 68, 95, 71, 96

Try This: Example 1 Continued

Step 2: Find the number of data values in each interval. Write these numbers in the “Frequency” column.

English Exam GradesGrades Frequency Cumulative

Frequency

60–69

70–79

80–89

90–99

4

4

6

6

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the grades received on an English exam. Make a cumulative frequency table of the data.

85, 84, 77, 65, 99, 90, 80, 85, 95, 72, 60, 66, 94, 86, 79, 87, 68, 95, 71, 96

Try This: Example 1 Continued

Step 3: Find the cumulative frequency for each row by adding all the frequency values that are above or in that row.

English Exam GradesGrades Frequency Cumulative

Frequency

60–69

70–79

80–89

90–99

4

4

6

6

48

14

20

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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.

2 4 7 9

3 0 6

Stems Leaves

Key: 2|7 means 27

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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.

33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17

Additional Example 2: Organizing Data in a Stem-and-Leaf Plot

Step 1: Find the least data value and the greatest data value.Since the data values range from 12 to 40, use tens digits for the stems and ones digits for the leaves.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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.

33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17

Additional Example 2 Continued

Step 2: List the stems from least to greatest on the plot.

Stems Leaves

1234

The stems are the tens digits.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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.

33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17

Additional Example 2 Continued

Step 3: List the leaves for each stem from least to greatest.

Stems Leaves

1234

The stems are the tens digits.

2 5 5 7 7 8

0 1 2 3 3 93 3

0

The leaves are the ones digits.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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.

33, 40, 29, 33, 23, 22, 20, 21, 18, 23, 17, 15, 15, 12, 17

Additional Example 2 Continued

Step 4: Add a key and a title.

The stems are the tens digits.

Stems Leaves

1234

2 5 5 7 7 8

0 1 2 3 3 93 3

0

The leaves are the ones digits.

Number of Years Coached

Key: 2 | 1 means 21.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the number of students on twenty school buses.

55, 60, 33, 30, 23, 45, 28, 41, 62, 29, 35, 40, 43, 37, 68, 30, 61, 27, 38, 41

Try This: Example 2

Step 1: Find the least data value and the greatest data value.Since the data values range from 23 to 68, use tens digits for the stems and ones digits for the leaves.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the number of students on twenty school buses.

55, 60, 33, 30, 23, 45, 28, 41, 62, 29, 35, 40, 43, 37, 68, 30, 61, 27, 38, 41

Try This: Example 2 Continued

Step 2: List the stems from least to greatest on the plot.

Stems Leaves

23456

The stems are the tens digits.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the number of students on twenty school buses.

55, 60, 33, 30, 23, 45, 28, 41, 62, 29, 35, 40, 43, 37, 68, 30, 61, 27, 38, 41

Try This: Example 2 Continued

The stems are the tens digits.

Stems Leaves

23456

Step 3: List the leaves for each stem from least to greatest.

The leaves are the ones digits.3 7 8 9

0 0 3 5 7

0 1 1 3 55

0 1 2 8

8

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

The list shows the number of students on twenty school buses.

55, 60, 33, 30, 23, 45, 28, 41, 62, 29, 35, 40, 43, 37, 68, 30, 61, 27, 38, 41

Try This: Example 2 Continued

The stems are the tens digits.

Step 4: Add a key and a title.

The leaves are the ones digits.

Stems Leaves

23456

3 7 8 90 0 3 5 7

0 1 1 3 55

0 1 2 8

8

Number of Students on School Buses

Key: 4 | 0 means 40.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

Lesson Quiz

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

1. Make a cumulative frequency table of the data.

2. Make a stem-and-leaf plot of the data.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

Lesson Quiz

Nurses’ Ages

Ages Frequency Cumulative Frequency

20–29 5 5

30–39 7 12

40–49 4 16

50–59 2 18

60–69 2 20

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots

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

1. Make a cumulative frequency table of the data.

Lesson Quiz

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

2. Make a stem-and-leaf plot of the data.

Stems Leaves

23456

1 3 3 4 41 3 4 5 5 8 9

2 5 5 5 7 7 0 1

Nurses’ Ages

Key: 4 | 2 means 42.

Course 2

1-3 Frequency Tables and Stem-and-Leaf Plots