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1 For which of the following correlations would the data points be clustered most closely around a straight line?
A. r = 0.50 B. r = -0.80 C. r = 0.10
D. There is no relationship between the correlation and how close the data points are to the line
Answer Point Value: 0.5 points Answer Key: B
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (- ), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE:
For scientific notation, a period MUST be used as the decimal point marker.
For the following set of scores, Pearson's r is ____. (Round your final answer to two decimal places.)
X Y
2 6
3 4
4 6
2 7
4 2
Answer Point Value: 0.5 points Answer Key: -.63|-.62
3 Accepted characters: numbers, decimal point markers (period or comma), sign indicators (- ), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE:
For scientific notation, a period MUST be used as the decimal point marker.
For the following set of scores, Pearson's r is ____. (Round your final answer to two decimal places.)
X Y
1 5
5 2
6 9
15 20
8 4
Answer Point Value: 0.5 points Answer Key: 0.82
correlation of +1.00
Answer Point Value: 0.5 points Answer Key: A
5 A set of n = 15 pairs of scores (X and Y values) has SSX = 4, SSY = 25, and SSXY = 6. The Pearson correlation for these data is
A. 6 B. 0.06 C. 0.006 D. 0.60
Answer Point Value: 0.5 points Answer Key: D
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (- ), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE:
For scientific notation, a period MUST be used as the decimal point marker.
For the following set of scores, Pearson's r is ____. (Round your final answer to two decimal places.)
X Y
1 0
4 4
3 1
2 1
Answer Point Value: 0.5 points Answer Key: 0.89
7 Accepted characters: numbers, decimal point markers (period or comma), sign indicators (- ), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE:
For scientific notation, a period MUST be used as the decimal point marker.
A set of n = 4 pairs of scores (X and Y values) has SSX = 5, SSY = 625, and SSXY = 50.
The coefficient of determination (R2) for these data is ____. (Round your answer to two decimal places.)
Answer Point Value: 0.5 points Answer Key: .79|.80
8 A college professor reports that students who finish exams early tend to get better grades than students who hold on to exams until the last possible moment. The correlation between exam score and amount of time spent on the exam is an example of
A. a positive correlation B. a negative correlation C. a correlation near one D. a correlation near zero
Answer Point Value: 0.5 points Answer Key: B
D. strong, negative
Answer Point Value: 0.5 points Answer Key: B
10 Sketch a scatterplot of the following data. Is the relationship between the variables positive or negative?
X Y
3 12
6 7
3 9
5 7
3 10
A. positive B. negative
Answer Point Value: 0.5 points Answer Key: B
Identify the strength and direction of the relationship among the two variables shown in the graph.
Attachments corr6.pdf
A. weak, negative B. weak, positive C. strong, positive D. strong, negative
Answer Point Value: 0.5 points Answer Key: D
12 In the following data, there are three scores (X, Y, and Z) for each of the n = 5 individuals.
Sketch a scatterplot for each of the relationships. The correlation between X and Y is ____, between X and Z is ____, and between Y and Z is ____.
X Y Z
3 5 5
4 3 2
2 4 6
1 1 3
0 2 4
A. negative, positive, negative B. positive, positive, negative C. negative, negative, positive D. positive, negative, positive
Answer Point Value: 0.5 points Answer Key: D
Answer Point Value: 0.5 points Answer Key: A
14 The following graph displays a linear relationship between liking and self-disclosure.
Attachments corr3.pdf
True False
Answer Point Value: 0.5 points Answer Key: False
15 Accepted characters: numbers, decimal point markers (period or comma), sign indicators (- ), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE:
For scientific notation, a period MUST be used as the decimal point marker.
X Y X - MX Y - MY (X - MX) (Y
- MY)
9 4 9 - 8 = 1 4 - 5 = -1 (1) * (-1) = -
1
7 7
6 3
10 6
Complete the above table and compute the covariance. The covariance (SSXY) for these data is ____.
Answer Point Value: 0.5 points Answer Key: 3
Identify the strength and direction of the relationship among the two variables shown in the graph.
Attachments corr11.pdf
A. weak, negative B. strong, negative C. strong, positive D. weak, positive
Answer Point Value: 0.5 points Answer Key: A
17 Identify the strength and direction of the relationship among the two variables shown in the graph.
Attachments corr14.pdf
A. weak, positive B. weak, negative C. strong, positive D. strong, negative
Answer Point Value: 0.5 points Answer Key: C
D. For each Y score, the distribution of X scores is normally distributed
E. All of the above
Answer Point Value: 0.5 points Answer Key: E
19 Violation of the assumption of homoscedasticity means that A. the variances of X and Y are negative
B. the variance in Y is different from the variance in X
C. there is a negative correlation between X and Y
D. the variance in Y is the same as the variance in X
Answer Point Value: 0.5 points Answer Key: B
20 Correlation values can range from -1.0 to +1.0.
True False
Answer Point Value: 0.5 points Answer Key: True
