4-2
4-2 Organizing
OrganizingData
Data
Warm Up
Problem of the Day
Lesson Presentation
Pre-Algebra
Pre-Algebra
4-2 Organizing Data
Warm Up
Compare. Write < or >.
1. 3(6) > 15
2. 53 – 37 < 19
3. 27 < 2(14)
4. 49 – (–4) > 51
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-leafoplot
back-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
Monday
Tuesday
To the Park
12
13
Back Home
14
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)
2 5 = 25
Leaf = last digit
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 25
Key: 1 2 means 12
4 011
5 279
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 36
Key: 2 3 means 23
3 789
4 256
The data values are:
23, 26, 37, 38, 39, 42, 45, and 46.
Pre-Algebra
4-2 Organizing Data
Additional Example 3: Organizing data in Stem-andLeaf Plots
Use the given data to make a stem-and-leaf plot.
4 235
5 0
6 14
Pre-Algebra
Key: 4 2 means 42 mi/h
Speeds range from
42 to 64 so stems
are 4 to 6.
4-2 Organizing Data
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%
27%
25%
30%
2 3 5 7 7 8 Key: 2 3 means 23%
Percentage range
3 0
from 23 to 30 so
stems are 2 to 3.
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 Data
Additional Example 4: Organizing data in Back-toBack Stem-and-Leaf Plots
Use the given data to make a back-to-back stemand-leaf plot.
1950
48
5
1
3
Pre-Algebra
2000
1 0599
2 9
3
4
Key: | 2 | 9 means 29
representatives 8 | 1 |
means 18 representatives
4-2 Organizing Data
Try This: Example 4
Use the given data to make a back-to-back stemand-leaf plot.
Voting Statistics
Voted
Did 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
Age
Pre-Algebra
Did not vote
Voted
5 5 8 0 8
4 8 1 0 2 6 6
0 1 2 3 4
Key: | 0 | 8 means 8 million
people
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.
Pre-Algebra
3
2
4
3
5
2.5
Full
Partial
None
4-2 Organizing Data
Lesson Quiz: Part 2
2. List the data values in the stem-and-leaf plot.
0 69
Key: 1 4 means 14
1 47
2 25
Pre-Algebra
6, 9, 14, 17, 22, 25