# Bivariate data: Correlation

Below are four bivariate data sets. (Note that each scatter plot is displayed on the same scale.) Each data set is made up of sample values drawn from a population.

x y = Figure 1

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1.0 8.0

2.0 4.8

3.0 9.8

4.0 6.2

5.0 2.0

6.0 4.8

7.0 8.9

8.0 4.0

9.0 9.7

10.0 6.7

u v = Figure 2

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1.0 7.4

2.0 8.5

3.0 7.0

4.0 5.3

5.0 7.8

6.0 4.8

7.0 4.0

8.0 7.1

9.0 5.9

10.0 4.2

w t = Figure 3

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1.0 10.0

2.0 9.0

3.0 8.0

4.0 7.0

5.0 6.0

6.0 5.0

7.0 4.0

8.0 3.0

9.0 2.0

10.0 1.0

m n = Figure 4

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1.0 2.8

2.0 4.0

3.0 3.7

4.0 5.5

5.0 4.7

6.0 6.8

7.0 5.7

8.0 7.7

9.0 6.7

10.0 8.0

Answer the following questions. The same response may be the correct answer for more than one question.

1. For which data set is the sample correlation coefficient r equal to -1? _______

a. the x, y data set

b. the u, v data set

c. the w, t data set

d. the m, n data set

e. none of the data sets

2. Which data set has an apparent positive, but not perfect, linear relationship between its two variables? ______

a. the x, y data set

b. the u, v data set

c. the w, t data set

d. the m, n data set

e. none of the data sets

3. Which data set indicated the strongest negative linear relationship between its two variables?

a. the x, y data set

b. the u, v data set

c. the w, t data set

d. the m, n data set

4. For which data set is the sample correlation coefficient r closest to 0?

a. the x, y data set

b. the u, v data set

c. the w, t data set

d. the m, n data set

#### Solution Summary

Answers 4 multiple choice questions.