Question 1

In a test for significance of a Pearson correlation for a sample of n = 30 individuals, you determine the critical value by using df = 29.

Accepted Answer

A) True 
 B)False

Question 2

A set of n = 15 pairs of scores (X and Y values)  has SSX = 4, SSY = 25, and SP = 6.The Pearson correlation for these data is

Accepted Answer

A)  6/100
B)  6/10
C)  6/(100/15) 
D)  6/(10/√15) E) B) and C)
F) A) and C)

Question 3

How large a sample is needed for a correlation of r = 0.550 to be significant using a two-tailed test with α = .05?

Accepted Answer

A)  n = 14
B)  n = 13
C)  n = 12
D)  n = 11E) A) and B)
F) A) and C) A

Question 4

Assuming that other factors are constant, a correlation of r = -0.95 will result in more accurate predictions than a correlation of r = +0.70.

Accepted Answer

A) True 
 B)False

Question 5

The value for the sum of products (SP) is always greater than or equal to zero.

Accepted Answer

A) True 
 B)False

Question 6

What is indicated by a Pearson correlation of r = +1.00 between X and Y?

Accepted Answer

A)  each time X increases, there is a perfectly predictable increase in Y
B)  every change in X causes a change in Y
C)  every increase in X causes an increase in Y
D)  All of the other 3 choices occur with a correlation of +1.00.E) A) and B)
F) A) and C)

Question 7

The value for a correlation can never be greater than +1.00.

Accepted Answer

A) True 
 B)False

Question 8

What is indicated by a positive value for a correlation?

Accepted Answer

A)  increases in X tend to be accompanied by increases in Y
B)  increases in X tend to be accompanied by decreases in Y
C)  a much stronger relationship than if the correlation were negative
D)  a much weaker relationship than if the correlation were negativeE) B) and D)
F) A) and B)

Question 9

The Pearson and the Spearman correlations are both computed for the same set of data.If the Spearman correlation is rS = +1.00, then what can you conclude about the Pearson correlation?

Accepted Answer

A)  It will be positive.
B)  It will have a value of 1.00
C)  It will be positive and have a value of 1.00
D)  There is no predictable relationship between the Pearson and the Spearman correlationsE) C) and D)
F) B) and C)

Question 10

For which of the following Pearson correlations would the data points be clustered most closely around a straight line?

Accepted Answer

A)  r = -0.10
B)  r = +0.40
C)  r = -0.70
D)  There is no relationship between the correlation and how close the points are to a straight line.E) B) and C)
F) All of the above

Question 11

The Spearman correlation is used to measure the relationship when both variables have been measured on an ordinal scale (both are ranks).

Accepted Answer

A) True 
 B)False

Question 12

For a two-tailed hypothesis test evaluating a Pearson correlation, what is stated by the null hypothesis?

Accepted Answer

A)  there is a non-zero correlation for the general population
B)  the population correlation is zero
C)  there is a non-zero correlation for the sample
D)  the sample correlation is zeroE) B) and C)
F) A) and B)

Question 13

If the data points in a scatter plot show a nearly circular pattern, then the correlation is near zero.

Accepted Answer

A) True 
 B)False

Question 14

A researcher obtains SSX = 20, SSY = 5, and SP = 7 for a set of n = 25 pairs of scores.The Pearson correlation for these scores is r = 7/10 = 0.70.

Accepted Answer

A) True 
 B)False

Question 15

A researcher classifies people by gender and by whether or not they routinely watch the evening news on television.For the resulting data, the correct method for measuring the relationship between the two variables would be the phi-coefficient.

Accepted Answer

A) True 
 B)False

Question 16

For a two-tailed hypothesis test evaluating the significance of a correlation, the null hypothesis states that the sample correlation is zero.

Accepted Answer

A) True 
 B)False  False

Question 17

Which correlation should be used to measure the relationship between gender and grade point average for a group of college students?

Accepted Answer

A)  Pearson correlation
B)  Spearman correlation
C)  point-biserial correlation
D)  phi-coefficientE) B) and C)
F) C) and D)

Question 18

For a group of graduating college seniors, a researcher records each student's rank in his/her high school graduating class and the student's rank in the college graduating class.Which correlation should be used to measure the relationship between these two variables?

Accepted Answer

A)  Pearson correlation
B)  Spearman correlation
C)  point-biserial correlation
D)  phi-coefficientE) All of the above
F) B) and D) B

Question 19

A researcher obtains a Pearson correlation of r = 0.43 for a sample of n = 20 participants.For a two-tailed test, which of the following accurately describes the significance of the correlation?

Accepted Answer

A)  The correlation is significant with α = .05 but not with α = .01.
B)  The correlation is significant with either α = .05 or α = .01.
C)  The correlation is not significant with either α = .05 or α = .01.
D)  There is not enough information to evaluate the significance of the correlation.E) A) and D)
F) B) and C)

Question 20

What would the scatterplot show for data that produce a Pearson correlation of r = +.88?

Accepted Answer

A)  points clustered close to a line that slopes up to the right
B)  points clustered close to a line that slopes down to the right
C)  points widely scattered around a line that slopes up to the right
D)  points widely scattered around a line that slopes down to the rightE) C) and D)
F) B) and D)

Exam 15: Correlation

In a test for significance of a Pearson correlation for a sample of n = 30 individuals, you determine the critical value by using df = 29.

Correct AnswerverifiedShow Answer

A set of n = 15 pairs of scores (X and Y values) has SSX = 4, SSY = 25, and SP = 6.The Pearson correlation for these data is

Correct AnswerverifiedShow Answer

How large a sample is needed for a correlation of r = 0.550 to be significant using a two-tailed test with α = .05?

Correct AnswerverifiedA

Assuming that other factors are constant, a correlation of r = -0.95 will result in more accurate predictions than a correlation of r = +0.70.

Correct AnswerverifiedShow Answer

The value for the sum of products (SP) is always greater than or equal to zero.

Correct AnswerverifiedShow Answer

What is indicated by a Pearson correlation of r = +1.00 between X and Y?

Correct AnswerverifiedShow Answer

The value for a correlation can never be greater than +1.00.

Correct AnswerverifiedShow Answer

What is indicated by a positive value for a correlation?

Correct AnswerverifiedShow Answer

The Pearson and the Spearman correlations are both computed for the same set of data.If the Spearman correlation is rS = +1.00, then what can you conclude about the Pearson correlation?

Correct AnswerverifiedShow Answer

For which of the following Pearson correlations would the data points be clustered most closely around a straight line?

Correct AnswerverifiedShow Answer

The Spearman correlation is used to measure the relationship when both variables have been measured on an ordinal scale (both are ranks).

Correct AnswerverifiedShow Answer

For a two-tailed hypothesis test evaluating a Pearson correlation, what is stated by the null hypothesis?

Correct AnswerverifiedShow Answer

If the data points in a scatter plot show a nearly circular pattern, then the correlation is near zero.

Correct AnswerverifiedShow Answer

A researcher obtains SSX = 20, SSY = 5, and SP = 7 for a set of n = 25 pairs of scores.The Pearson correlation for these scores is r = 7/10 = 0.70.

Correct AnswerverifiedShow Answer

A researcher classifies people by gender and by whether or not they routinely watch the evening news on television.For the resulting data, the correct method for measuring the relationship between the two variables would be the phi-coefficient.

Correct AnswerverifiedShow Answer

For a two-tailed hypothesis test evaluating the significance of a correlation, the null hypothesis states that the sample correlation is zero.

Correct AnswerverifiedFalse

Which correlation should be used to measure the relationship between gender and grade point average for a group of college students?

Correct AnswerverifiedShow Answer

For a group of graduating college seniors, a researcher records each student's rank in his/her high school graduating class and the student's rank in the college graduating class.Which correlation should be used to measure the relationship between these two variables?

Correct AnswerverifiedB

A researcher obtains a Pearson correlation of r = 0.43 for a sample of n = 20 participants.For a two-tailed test, which of the following accurately describes the significance of the correlation?

Correct AnswerverifiedShow Answer

What would the scatterplot show for data that produce a Pearson correlation of r = +.88?

Correct AnswerverifiedShow Answer

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A set of n = 15 pairs of scores (X and Y values) has SS_X = 4, SS_Y = 25, and SP = 6.The Pearson correlation for these data is

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A

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The Pearson and the Spearman correlations are both computed for the same set of data.If the Spearman correlation is r_S = +1.00, then what can you conclude about the Pearson correlation?

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A researcher obtains SS_X = 20, SS_Y = 5, and SP = 7 for a set of n = 25 pairs of scores.The Pearson correlation for these scores is r = 7/10 = 0.70.

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False

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B

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