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definitions

A scatter plot is a graph that relates data from two different sets. To make a scatter plot, the two sets of data are plotted as ordered pairs.

A TEST OF TELEVISION…

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ed

Test Score

Hours watch

ed

Test score

0 98 5 85

1 85 5 75

1 50 5 68

2 82 6 58

3 75 7 75

3 97 7 65Plot as (3, 97)

example

1) Two students watched 3 hours of TV. What does the graph tell you about the students’ test scores?

2) a) A student scored a 58 on the test, how many hours of TV did he/she watch?

b) How can you tell by looking at the scatter plot?

exampleEach ordered pair represents (unit price, quantity sold) of various

items for sale in a store. Draw a scatter plot of the data.

($5.00, 56), ($9.99, 4), ($8.49, 21), ($1.09, 71), ($.35, 92), ($5.00, 32)

Analyzing trends in data

Positive Correlation Negative Correlation No Correlation

A trend line on a scatter plot shows a

correlation more clearly.

example

1) Is there a positivecorrelation, negativecorrelation, or no correlation?

2) What does each data point represent?

3) Predict the asking price of a Ford Taurus that is 7 years old.

homework

P. 58 #2-18 even