Pre-Algebra

4-2 Organizing Data4-2 Organizing Data

Pre-Algebra

Warm UpWarm Up

Problem of the DayProblem of the Day

Lesson PresentationLesson Presentation

Pre-Algebra

4-2 Organizing Data

Warm UpCompare. Write < or >.

1. 3(6) 15

2. 53 – 37 19

3. 27 2(14)

4. 49 – (–4) 51

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Pre-Algebra

4-2 Organizing Data

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Pre-Algebra

4-2 Organizing Data

Problem of the Day

If today is Wednesday, what day of the week will it be in 100 days?

Friday

Pre-Algebra

4-2 Organizing Data

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

Pre-Algebra

4-2 Organizing Data

Vocabulary

stem-and-leafoplotback-to-back stem-and-leafoplot

Pre-Algebra

4-2 Organizing Data

When you graduate and start looking for a job, you may have to keep track of a lot of information.

A table is one way to organize data so that you can understand the meaning and recognize any relationships.

Pre-Algebra

4-2 Organizing Data

Additional Example 1: Organizing Data in Tables

Use the given data to make a table.

Jack timed his bus rides to and from school. On Monday, it took 7 minutes to get to school and 9 minutes to get home. On Tuesday, it took 5 minutes and 9 minutes, respectively, and on Wednesday, it took 8 minutes and 7 minutes.

Pre-Algebra

4-2 Organizing Data

Try This Example: 1

Use the given data to make a table.

Jill timed herself jogging to the park and back home. On Monday she ran to the park in 12 minutes then back home in 14 minutes, on Tuesday it took her 13 and 15 minutes, respectively, and on Wednesday, it took her 11 minutes and 13 minutes.

Day To the Park Back Home

Monday 12 14

Tuesday 13 15

Wednesday 11 13

Pre-Algebra

4-2 Organizing Data

A stem-and-leaf plot is another way to display data. The values are grouped so that all but the last digit is the same in each category.

Stem = first digits(s)

Leaf = last digit

2 5 = 25

Pre-Algebra

4-2 Organizing Data

Additional Example 2: Reading Stem-and-Leaf Plots

List the data values of the stem-and-leaf plot.

1 2 5

4 0 1 1

5 2 7 9

Key: 1 2 means 12

The data values are:

12, 15, 40, 41, 41, 52, 57, and 59.

Pre-Algebra

4-2 Organizing Data

Try This: Example 2

List the data values of the stem-and-leaf plot.

2 3 6

3 7 8 9

4 2 5 6

Key: 2 3 means 23

The data values are:

23, 26, 37, 38, 39, 42, 45, and 46.

Pre-Algebra

4-2 Organizing DataAdditional Example 3: Organizing data in Stem-and-Leaf

Plots

Use the given data to make a stem-and-leaf plot.

4 2 3 5

5 0

6 1 4

Key: 4 2 means 42 mi/hSpeeds range from 42 to 64 so stems are 4 to 6.

Pre-Algebra

4-2 Organizing Data

Try This: Example 3

Use the given data to make a stem-and-leaf plot.

2 3 5 7 7 8

3 0

Key: 2 3 means 23%Percentage range from 23 to 30 so stems are 2 to 3.

Percent of Persons under 18 years old, year 2000

Florida

California

Texas Arizona New York

Alaska

23% 27% 28% 27% 25% 30%

Pre-Algebra

4-2 Organizing Data

A back-to-back stem-and-leaf plot is used to compare two sets of data. The stems are in the center, and the left leaves are read in reverse.

Pre-Algebra

4-2 Organizing DataAdditional Example 4: Organizing data in Back-to-Back

Stem-and-Leaf PlotsUse the given data to make a back-to-back stem-and-leaf plot.

1 2 3 4

200019500 5 9 9 4 8

5 1 3

Key: | 2 | 9 means 29 representatives 8 | 1 | means 18 representatives

9

Pre-Algebra

4-2 Organizing Data

Try This: Example 4

Use the given data to make a back-to-back stem-and-leaf plot.

0 8

1 0 2 6 6

2 3 4

Voting Statistics

Age VotedDid not

vote

Millions Millions

18 to 24 years 8 18

25 to 34 years 16 21

35 to 44 years 24 20

45 to 54 years 23 14

55 to 64 years 16 8

65 to 74 years 12 5

75 years up 10 5

Did not vote Voted5 5 8

4 8

0 1

Key: | 0 | 8 means 8 million people

Pre-Algebra

4-2 Organizing Data

Lesson Quiz: Part 1

Use the given data to make a table.

1. There are three houses. The first house has 3 bedrooms, 2 bathrooms, and a full basement. The second house has 4 bedrooms, 3 bathrooms, and a partial basement. The third house has 5 bedrooms, 2.5 bathrooms, and no basement.

32

Full

43

Partial

52.5

None

Pre-Algebra

4-2 Organizing Data

Lesson Quiz: Part 2

2. List the data values in the stem-and-leaf plot.

0 6 9

1 4 7

2 2 5

Key: 1 4 means 14

6, 9, 14, 17, 22, 25