scatter plots by irma crespo 2010. definition a scatter plot is a graph that shows the relationship,...
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Scatter Plots
By Irma Crespo 2010
Definition
A scatter plot is a graph that shows the relationship, if any relationship exists, between two sets of data.
Scatter plots often show a pattern, trend, or relationship.
They are useful for making predictions or for finding out the connection between two sets of data.
Types of Relationships
As x increases,y increases
Positive Relationship
y
x0
y
x0
y
x0
Negative Relationship
No Relationship
As x increases,y decreases
No obvious pattern
Identify the RelationshipLook at the Graph
3002001000
12
4
8
Distance Traveled (mi)
Fu
el R
emai
nin
g (g
al) y
x
Negative
As the distance traveled in miles increases, the fuel in gallons decreases.
As x increases, y decreases.
Identify the RelationshipLook at the Graph
2 108640
10
20
30
40
50
Experience (weeks)
Key
boa
rd S
pee
d (
wp
m)
y
x
Positive
As the number of weeks of experience increases, the keyboarding speed increases.
As x increases, y increases.
Identify the RelationshipLook at the Graph
6 109870
12
10.8
11.2
11.6
Shoe Size
Ru
nn
ing
(s)
y
x
12.4
No obvious pattern.
No relationship
The time in running does not depend on shoe size.
Identify the RelationshipLook at the Graph
10 504030200
90
60
70
80
Study Time (minutes)
Tes
t S
core
y
x
100 Positive
As the number of study time increases, the test score increases.
As x increases, y increases.
What’s the relationship? Use Common Sense
and
your age your grade level
Positive Relationship
What’s the relationship? Use Common Sense
and
Negative Relationshi
p
number of written words
amount of ink
What’s the relationship? Use Common Sense
and
Positive Relationshi
p
time spent studying
grade on test
Grade
What’s the relationship? Use Common Sense
and
No Relationshi
p
the temperature
outside
your height
What’s the relationship? Use Common Sense
and
Negative Relationshi
p
number of times a pencil is sharpened
the length of the pencil
300 35 40 45
70
20
10
5 10 15 20 25
50
40
30
60
80
Average
Maxim
um
Line of (Best) FitMeasuring the Relationship
The table below shows the average and maximum longevity of various animals in captivity.
Longevity (years)
Average Maximum
12 47
25 50
15 40
8 20
35 70
40 77
41 61
20 54
Getting the slope:• Get two points.• Compute for rise divided by run.
(15, 40)
(35, 70)
y = 3/2 x + 18
Exit Slip
On a separate sheet of paper, answer the following: Example of a positive relationship.
Example of a negative relationship.
Example of no relationship.
Practice Worksheet
Complete the practice worksheet.
Work with a partner or on your own.
Submit completed worksheet for grading.
Solutions are discussed the next day.
Main Resources
Day, et.al. (2009). Math Connects: Concepts, Skills, and Problem Solving. Section 9.2. Columbus:McGraw-Hill.
PowerPoint created by Irma Crespo. University of Michigan-Dearborn, School of
Education. Winter 2010.