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Warm UpWarm Up

Lesson PresentationLesson Presentation

Problem of the DayProblem of the Day

Lesson QuizzesLesson Quizzes

Scatter Plots9-9

Warm Up

Graph each point on the same coordinate plane.

1. A (5, 20)

2. B (20, 15)

3. C (10, 40)

4. D (30, 35)A

B

CD

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Problem of the DayWhat is the least number that can be divided evenly by each of the numbers 1 through 12?

27,720

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Learn to create and interpret scatter plots.

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Vocabulary

scatter plotcorrelationline of best fit

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A scatter plot is a graph with points plotted to show a relationship between two sets of data.

Correlation describes the type of relationship between two data sets.

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Positive correlation: both data sets increase together.

Negative correlation: as one data set increases, the other decreases.

No correlation: changes in one data set do not affect the other data set.

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Use the given data to make a scatter plot of the weight and height of each member of a basketball team, and describe the correlation.

Additional Example 1: Making a Scatter Plot of a Data Set

The points on the scatter plot are (71, 170), (68, 160), (70, 175), (73, 180), and (74, 190).There is a positive correlation between the two data sets.

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Use the given data to make a scatter plot of the weight and height of each member of a soccer team, and describe the correlation.

Check It Out: Example 1

12062

13568

17569

15667

12563

Weight (lbs)Height (in)200

190

180

170

160

150

140

130

120

60 61 62 63 64 65 66 67 68 69

The points on the scatter plot are (63, 125), (67, 156), (69, 175), (68, 135), and (62, 120). Height

Weig

ht

There is a positive correlation between the two data sets.

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Make a scatter blot of the data, and draw a line of best fit. Then use the data to predict how much a worker will earn in tips in 10 hours.

Additional Example 2: Using a Scatter plot to Make Predictions

Tips earned may be dependent on the number of hours worked.

Step 1: Make a scatter plot.

Let hours worked represent the independent variable x and tips earned represent the dependent variable y.

Scatter Plots9-9Additional Example 2 Continued

Step 2: Draw a line of best fit.

Draw a line that has about the same number of points above and below it.

Scatter Plots9-9Additional Example 2 Continued

Step 3: Make a prediction.

According to the graph, working 10 hours will earn about $24 in tips.

Find the point on the line whose x-value is 10. The corresponding y-value is about 24.

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Use the data to predict how many circuit boards a worker will assemble in 10 hours.

Check It Out: Example 3

According to the graph, a worker will assemble approximately 10 circuit boards in 10 hours.

Hours Worked

4 8 6 9 11

Circuit Board Assemblies

2 7 5 8 12

141210 8 6 4 2

2 4 6 8 10 12 14

Hou

rs

Circuit Board Assemblies

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Standard Lesson Quiz

Lesson Quizzes

Lesson Quiz for Student Response Systems

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Lesson Quiz: Part I

1. Use the given information to make a scatter plot, and describe the correlation.

Grading Period 1 2 3 4

Number of A’s 5 6 8 10

positive correlation

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Lesson Quiz: Part II

2. Draw a line of best fit for the scatter plot you drew in Problem 1. Then use the data to predict the number of A’s in grading period 6.

approximately 13 A’s

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1. Identify a scatter plot for the given data.

A. B.

Lesson Quiz for Student Response Systems

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2. Do the data sets have a positive, a negative, or no correlation?distance covered and time taken at constant speed

A. positive

B. negative

C. none

Lesson Quiz for Student Response Systems

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3. Do the data sets have a positive, a negative, or no correlation?value of a used car and the total distance traveled

A. positive

B. negative

C. none

Lesson Quiz for Student Response Systems