Deck 10: Describing Relationships Using Correlation and Regression

Question 1

What does a correlation coefficient do?

A)It allows us to draw conclusions about whether one variable causes another variable.
B)It creates a correlational design, rather than an experimental design.
C)It simplifies a complex pattern involving many scores into one easily interpreted statistic.
D)It summarizes the X scores and the Y scores separately.

Answer 1

C

Question 2

When the correlation coefficient representing the relationship between X and Y is intermediate, then all of the following are true except

A)there is not a perfectly consistent association.
B)there are different Y scores associated with a single X score.
C)prediction of Y from a known X score has some error.
D)all data points fall on the regression line.

Answer 2

D

Question 3

Dr.Johnston has calculated a correlation between the number of cigarettes smoked per week and the age of his patients at the point of their first heart attack as r = -0.92.Dr.Johnston and his associates claim there apparently is no relationship between smoking and heart attacks.What error has Dr.Johnson made?

A)No error has been made; an r = -0.92 is so close to 0 that there is no relationship.
B)A correlation coefficient this close to -1 means there probably is a relationship, but we probably should do a significance test just to be sure.
C)Not everyone who smokes has a heart attack.
D)Dr.Johnston should know there are numerous factors involved when a person has a heart attack.

Answer 3

B

Question 4

"The more you save, the less you spend" describes

A)a positive linear correlation.
B)a negative linear correlation.
C)no correlation.
D)a nonlinear correlation.

Question 5

The best-fitting line through a scatterplot is known as the

A)linear scatterplot line.
B)linear correlation line.
C)linear variance line.
D)linear regression line.

Question 6

In general, a positive correlation means as the values of one variable , there is a tendency for the values of the other variable to .

A)increase; increase
B)increase; decrease
C)decrease; increase
D)decrease; decrease

Question 7

A linear regression procedure should ultimately yield a value called

A)Y prime.
B)rho.
C)the slope.
D)the proportion of variance accounted for.

Question 8

When plotting correlational data, the appropriate graph to use is the

A)line graph.
B)bar graph.
C)histogram.
D)scatterplot.

Question 9

"The bigger they are, the harder they fall" describes

A)a positive linear correlation.
B)a negative linear correlation.
C)no correlation.
D)a nonlinear correlation.

Question 10

If you have a Pearson correlation coefficient of .30, what is the proportion of variance accounted for?

A).09
B).90
C).60
D).30

Question 11

The values of rho are

A)between -1 and +1.
B)unrestricted.
C)between 0 and +1.
D)any positive number.

Question 12

Which of the following r-values indicates the weakest relationship between two variables?

A)+0.45
B)-0.30
C)+0.03
D)-0.45

Question 13

Which relationship is stronger, r = +0.62 or r = -0.62?

A)An r = +0.62 represents a stronger relationship than r = -0.62.
B)An r = -0.62 represents a stronger relationship than r = +0.62.
C)There is no difference in the strength of the two relationships.
D)Without seeing a scatterplot of the data, there is no way to determine which is stronger.

Question 14

Professor Miller has found the correlation between a person's "need for affiliation" found by taking a test to determine the need to be with others) and the number of hours spent watching television is −0.69.He should conclude

A)as we observe people with higher and higher need for affiliation, we see a tendency for those people to spend less and less time watching television.
B)there is not much of a relationship between the two variables because the r is negative.
C)as we observe people with higher and higher need for affiliation, we see a tendency for those people to spend more and more time watching television.
D)the people who watch more television tend to have more need to be around others.

Question 15

Which of the following r-values indicates the strongest relationship between two variables?

A)+0.65
B)-0.89
C)+0.10
D)-0.10

Question 16

We should do a scatterplot of the data when we compute a correlation because the scatterplot allows us to

A)see the particular relationship and map out the best way to summarize it.
B)determine the exact value of the correlation coefficient.
C)determine whether a relationship is likely to exist in the population from which the sample is taken.
D)predict accurate Y scores for known X scores.

Question 17

A U-shaped pattern is an example of a

A)curvilinear relationship.
B)non-relationship.
C)positive relationship.
D)negative relationship.

Question 18

In general, a zero correlation means

A)as the values of one variable increase, there is no tendency for the values of the other variable to change in any consistent, predictable fashion.
B)as the values of one variable increase, there is a tendency for the values of the other variable also to increase.
C)as the values of one variable increase, there is a tendency for the values of the other variable to decrease.
D)as the values of one variable decrease, there is a tendency for the values of the other variable also to decrease.

Question 19

In a linear relationship, as the X scores increase, the Y scores change

A)in only one direction.
B)only in the negative direction.
C)only in the positive direction.
D)in the positive and then in the negative direction.

Question 20

What are the consequences of having a restricted range?

A)Obtaining a smaller r than otherwise would be the case.
B)Obtaining a larger r than otherwise would be the case.
C)Having a curvilinear instead of a linear relationship.
D)Having a correlation with a different direction than otherwise would be found.

Question 21

What kind of relationship is depicted in the following graph?

Question 22

Suppose you've done a study and you're writing up your results for presentation in an APA journal.You want to report a significant correlation of -.72 with degrees of freedom of 51.How would you report this?

Question 23

Suppose income and personal health are correlated at .35.What can you say about cause and effect?

Question 24

Suppose you find that sleepiness and happiness are correlated at -.65.What does this value tell us in terms of what percentage of happiness is not associated with sleepiness?

Question 25

What kind of relationship is depicted in the following graph?

Question 26

If the correlation coefficient for X and Y is calculated to be -.95, what is the proportion of variance accounted for?

Question 27

Suppose you are trying to predict how a child's IQ is impacted by their mother's IQ.State the criterion and predictor variables.

Question 28

What kind of relationship is depicted in the following graph?

Question 29

Use the following data set and conduct a two-tailed test of significance on the Pearson r.Use = .05.
a.What are your null and alternative hypotheses?
b.What are your degrees of freedom?
c.What is the critical value?
d.Calculate the Pearson r
e.What do you conclude?

Question 30

What type of relationship does the following regression line represent?

Question 31

If the proportion of variance accounted for is 36%, what is the correlation coefficient for X and Y?

Question 32

Suppose a researcher is trying to figure out how one's anxiety may predict depression scores.What are the criterion and predictor variables?

Question 33

What kind of relationship is depicted in the following graph?

Question 34

What type of relationship does the following regression line represent?

Question 35

Use the following data set and conduct a two-tailed test of significance on the Pearson r.Use = .05.
a.What are your null and alternative hypotheses?
b.What are your degrees of freedom?
c.What is the critical value?
d.Calculate the Pearson r
e.What do you conclude?

Question 36

Dr.Phillips has conducted a correlational study with 112 subjects.However, she only has X and Y values for 107 of these subjects.What are the degrees of freedom in this study?

Question 37

What type of relationship does the following regression line represent?

Question 38

Suppose you've calculated a Pearson correlation coefficient and had a final value of +10.How do you interpret this result?

Question 39

Use the following data set and conduct a one-tailed test of significance in the upper tail on the Pearson r.Use =
.05.
a.What are your null and alternative hypotheses?
b.What are your degrees of freedom?
c.What is the critical value?
d.Calculate the Pearson r
e.What do you conclude?

Question 40

If the correlation coefficient for X and Y is calculated to be +.47, what is the proportion of variance accounted for?