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 Positive Relationship Negative Relationship No Relationship y x y x y x As x increases, y increases As x increases, y decreases No obvious pattern

Identify the Relationship Look at the Graph 300 200 100 12 4 8 Distance Traveled (mi) Fuel Remaining (gal) y x Negative As the distance traveled in miles increases, the fuel in gallons decreases. As x increases, y decreases.

Identify the Relationship Look at the Graph 2 10 8 6 4 20 30 40 50 Experience (weeks) Keyboard Speed (wpm) y x Positive As the number of weeks of experience increases, the keyboarding speed increases. As x increases, y increases.

Identify the Relationship Look at the Graph 6 10 9 8 7 12 10.8 11.2 11.6 Shoe Size Running (s) y x 12.4 No relationship The time in running does not depend on shoe size. No obvious pattern.

Identify the Relationship Look at the Graph 10 50 40 30 20 90 60 70 80 Study Time (minutes) Test Score 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 your age your grade level and Positive Relationship

What’s the relationship? Use Common Sense number of written words amount of ink and Negative Relationship

What’s the relationship? Use Common Sense time spent studying grade on test Grade and Positive Relationship

What’s the relationship? Use Common Sense your height the temperature outside and No Relationship

What’s the relationship? Use Common Sense number of times a pencil is sharpened the length of the pencil and Negative Relationship

Line of (Best) Fit Measuring the Relationship Getting the slope: Get two points. Compute for rise divided by run. The table below shows the average and maximum longevity of various animals in captivity. y = 3/2 x + 18 Longevity (years) Average Maximum 12 47 25 50 15 40 8 20 35 70 77 41 61 54 30 35 40 45 70 20 10 5 15 25 50 60 80 Average Maximum (35, 70) (15, 40)

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.