1. 4-2 Organizing Data Warm Up Problem of the Day Lesson Presentation
Pre-Algebra

2. 4-2 Organizing Data Warm Up Compare. Write < or >. 1. 3(6) 15
Pre-Algebra
4-2
Organizing Data
Warm Up
Compare. Write < or >.
1. 3(6)
2. 53 –
(14)
4. 49 – (–4)
>
<
<
>

3. Problem of the Day
If today is Wednesday, what day of the week will it be in 100 days?
Friday

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

5. Vocabulary
stem-and-leafoplot
back-to-back stem-and-leafoplot

6. 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.

7. 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.

8. 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

9. A stem-and-leaf plot is another way to display 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)
2 5 = 25
Leaf = last digit

10. Additional Example 2: Reading Stem-and-Leaf Plots
List the data values of the stem-and-leaf plot.
1 2 5
Key: 1 2 means 12
The data values are:
12, 15, 40, 41, 41, 52, 57, and 59.

11. 2 3 6 3 7 8 9 4 2 5 6 Key: 2 3 means 23 The data values are:
Try This: Example 2
List the data values of the stem-and-leaf plot.
2 3 6
Key: 2 3 means 23
The data values are:
23, 26, 37, 38, 39, 42, 45, and 46.

12. Additional Example 3: Organizing data in Stem-and-Leaf Plots
Use the given data to make a stem-and-leaf plot.
5 0
6 1 4
Key: 4 2 means 42 mi/h
Speeds range from 42 to 64 so stems are 4 to 6.

13. Percent of Persons under 18 years old, year 2000
Try This: Example 3
Use the given data to make a stem-and-leaf plot.
Percent of Persons under 18 years old, year 2000
Florida
California
Texas
Arizona
New York
Alaska
23%
27%
28%
25%
30%
3 0
Key: 2 3 means 23%
Percentage range from 23 to 30 so stems are 2 to 3.

14. A back-to-back stem-and-leaf plot is used to compare two sets of 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.

15. Key: | 2 | 9 means 29 representatives 8 | 1 | means 18 representatives
Additional Example 4: Organizing data in Back-to-Back Stem-and-Leaf Plots
Use the given data to make a back-to-back stem-and-leaf plot.
1950
2000
Key: | 2 | 9 means 29 representatives 8 | 1 | means 18 representatives
4 8
5 1 3 9

16. Use the given data to make a back-to-back stem-and-leaf plot.
Try This: Example 4
Use the given data to make a back-to-back stem-and-leaf plot.
Voting Statistics
Age
Voted
Did not vote
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
65 to 74 years 12 5
75 years up 10
Did not vote
Voted
4 8
0 1
0 8
Key: | 0 | 8 means 8 million people

17. 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. 3 4 5 2 3
2.5
Full
Partial
None

18. Lesson Quiz: Part 2
2. List the data values in the stem-and-leaf plot.
Key: 1 4 means 14
0 6 9
1 4 7
2 2 5
6, 9, 14, 17, 22, 25