7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots Problem of the Day Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day

7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots

Problem of the DayProblem of the Day

Warm UpWarm Up

Lesson Presentation

Problem of the Day

Lesson Quizzes


Warm Up

Jason deposits $200 in an account that earns 3.6% simple interest. How long until the total amount is $300?Almost 14 years


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


Prep for MA.7.S.6.2 Construct and analyze…stem-and-leaf plots…

Sunshine State Standards


Vocabulary

frequency tablecumulative frequencystem-and-leaf plotline plot


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.

The frequency of a data value is the number of times it occurs.

Remember!


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

Additional Example 1: Organizing and Interpreting Data in a Frequency Table

February Temperatures in 20 CitiesAverage

HighsFrequency

Cumulative Frequency

Step 1: Choose a scale that includes all of the data values. Then separate the scale into equal intervals.

0–19

20–39

40–59

60–79



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.


HighsFrequency


7

5

5

3

0–19

20–39

40–59

60–79



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


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


HighsFrequency


0–19

20–39

40–59

60–79

7

5

5

3

7

12

17

20

17 cities had average high temperature below 59 degrees.


Check It Out: Example 1

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


Check It Out: Example 1 Continued

English Exam GradesGrades Frequenc

yCumulative Frequency

60–69

70–79

80–89

90–99

4 4

4

6

6

8

14

20

8 students received a 79 or below.


A stem-and-leaf plot uses the digits of each number to organize and display a set of data. Each leaf on the plot represents the right-hand digit in a data value, and each stem represents the reamining left-hand digits.

2 4 7 9

3 0 6

Stems Leaves

Key: 2|7 means 27


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

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

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



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

Stems Leaves

1

2

3

4

The stems are the tens digits.


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



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

Stems Leaves

1

2

3

4


2 5 5 7 7 8

0 1 2 3 3 93 3

0

The leaves are the ones digits.


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



Step 4: Add a key and a title.


Stems Leaves

1

2

3

4

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.

11 coaches coached fewer than 25 years.


The table shows the number of points a playerscored during the last ten games of the season.Make a stem-and-leaf plot of the data. In howmany games did the player score less than 30points?


42

Mar 4

46Feb 20

43Mar 127Feb 18

31Feb 2734Feb 14

18Feb 2536Feb 7

PointsPoints

32 28Feb 23

Mar 3

GameDate GameDate


Check It Out: Example 2 Continued

Stem Leaves

1

2

3

4

8

7 8

1 2 4 6

2 3 6

3 games under 30 points

Key: 1|8 means 18


Make a line plot of the data. How many hours per day did Morgan babysit most often?

Additional Example 3: Organizing and Interpreting Data in a Line Plot

0633484Wk 4

2165860Wk 3

8607772Wk 2

2856460Wk 1

SuSFThWTM

Number of Babysitting Hours in July




Step 1: The data values range from 0 to 8. Draw a number line that includes this range.

0 1 2 3 4 5 6 7 8




Step 2: Put an X above the number on the number line that corresponds to the number of babysitting hours in July.

0 1 2 3 4 5 6 7 8

XXXX X

XXX

XX

XXX

XX

XXXXXX

XXX

XXXX

The greatest number of X’s appear above the number 6. This means that Morgan babysat most often for 6 hours.



6 7 8 9 10

The hourly rates Morgan got for her last 10 jobs were $6, $6, $8, $7, $8, $9, $6,$10, $8, $6. Make a line plot of the data. What was the most common hourly rate?

X

XXXX

XXX X X

$6 per hour is the most common rate


Standard Lesson Quiz

Lesson Quizzes

Lesson Quiz for Student Response Systems


Lesson Quiz: Part I

Nurses’ Ages

Ages Frequency


20–29 5 5

30–39 7 12

40–49 4 16

50–59 2 18

60–69 2 20

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. How many of the nurses are under the age of 40? 12



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. How many nurses are over the age of 45?

Stems Leaves

2

3

4

5

6

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.

4

Lesson Quiz: Part II



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? 45

20-29 30-39 40-49 50-59 60-69

XXXXX

XXXXXXX

XXXX

XX

XX

Lesson Quiz: Part III


1. The data shows the number of loaves of bread a bakery sold each day for a month. Identify a cumulative frequency table of the data. How many days did the bakery sell less than 30 loaves?12, 19, 27, 24, 19, 44, 8, 32, 21, 37, 15, 6, 16, 48, 26, 5, 14, 23, 6, 35, 37, 28, 47, 40

A. B.



2. The data shows the ages (in days) of puppies in a pet-care center. Identify a stem-and-leaf plot of the data. How many puppies were over the age of 20 days?24, 35, 29, 27, 38, 19, 7, 31, 28, 36, 22, 19, 12, 31, 6, 18, 33, 26, 15, 32, 23, 19, 5, 11, 4

A. B.



3. The data gives the shoe sizes of a group of students. Identify a line plot of the data. What shoe size occurs most often?8, 8, 7, 6, 9, 9, 10, 13, 11, 10, 8, 9, 12, 10, 9, 9, 13, 12, 9, 8, 10, 7

A. B.


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7-1 Frequency Tables, Stem-and-Leaf Plots, and Line Plots Problem of the Day Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day