Question 1

In analyzing the relationship between two variables, a scatter plot cannot be used to detect which of the following?

Accepted Answer

A causal relationship

Answer

A curvilinear relationship

Answer

A negative linear relationship

Answer

A positive linear relationship

Question 2

If the population correlation between two variables is determined to be -0.70, which of the following is known to be true?

Accepted Answer

There is a fairly strong negative linear relationship between the two variables.

Answer

There is a positive linear relationship between the two variables.

Answer

The scatter diagram for the two variables will be upward sloping from left to right.

Answer

An increase in one of the variables will cause the other variable to decline by 70 percent.

Question 3

If a pair of variables have a strong curvilinear relationship, which of the following is true?

Accepted Answer

The correlation coefficient will not be able to indicate the relationship is curved.

Answer

A scatter plot will not be needed to indicate that curvature is present

Answer

The correlation coefficient will be able to indicate that curvature is present.

Answer

The correlation coefficient will be equal to zero.

Question 4

Which of the following statements is correct?

Accepted Answer

Two variables that are uncorrelated with one another may still be related in a nonlinear manner.

Answer

Correlation implies causation.

Answer

The stronger the linear relationship between two variables, the closer the correlation coefficient will be to 1.0.

Answer

A scatter plot showing two variables with a positive linear relationship will have all points on a straight line.

Question 5

Assume that a medical research study found a correlation of -0.73 between consumption of vitamin A and the cancer rate of a particular type of cancer. This could be interpreted to mean:

Accepted Answer

The more vitamin A consumed, the lower a person's chances are of getting this type of cancer.

Answer

The less vitamin A consumed, the lower a person's chances are of getting this type of cancer.

Answer

The more vitamin A consumed, the higher a person's chances are of getting this type of cancer.

Answer

Vitamin A causes this type of cancer

Question 6

The term that is given when two variables are correlated but there is no apparent connection between them is:

Accepted Answer

Spurious correlation

Answer

Random correlation

Answer

Spontaneous correlation

Answer

Linear correlation

Question 7

What is the range of possible values for the correlation coefficient?

Accepted Answer

-1 to 1

Answer

-∞ to ∞

Answer

1 to ∞

Answer

0 to 1

Question 8

If the correlation coefficient is zero, what does it mean?

Accepted Answer

None of the above

Answer

There is a perfect positive relationship between the two variables

Answer

There is no relationship between the two variables

Answer

There is a perfect negative relationship between the two variables

Question 9

Which of the following statements is true about covariance?

Accepted Answer

It can be positive or negative

Answer

It is always negative

Answer

It is always zero

Answer

It is always positive

Question 10

What is the difference between correlation and covariance?

Accepted Answer

Correlation can be interpreted as a measure of both the strength and direction of the linear relationship between two variables, while covariance is usually used only to indicate the direction of the relationship.

Answer

Correlation measures the strength of the linear relationship between two variables, while covariance measures the strength of the non-linear relationship between two variables.

Answer

Correlation measures the strength of the association between two variables, while covariance measures the direction of the relationship between two variables.

Answer

Correlation and covariance are interchangeable terms for measuring the same thing.

Question 11

What is a residual in regression analysis?

Accepted Answer

The difference between the predicted value and the actual value of the dependent variable

Answer

The difference between the mean value and the actual value of the dependent variable

Answer

The difference between the mean value and the actual value of the independent variable

Answer

The difference between the predicted value and the actual value of the independent variable

Question 12

How is covariance calculated?

Accepted Answer

By dividing the sum of the products of deviations from the means by the sample size minus one

Answer

By multiplying the standard deviation of one variable by the standard deviation of another variable

Answer

By subtracting the mean of one variable from the mean of another variable

Answer

By adding the variances of two variables together

Question 13

Can covariance be used to infer causation?

Accepted Answer

No, covariance only measures the strength of a linear relationship, not causation.

Answer

Sometimes, depending on the context and other factors.

Answer

It is unclear whether covariance can be used to infer causation without additional information.

Answer

Yes, a high covariance indicates that one variable causes another variable.

Question 14

Which of the following is an example of spurious correlation?

Accepted Answer

The correlation between ice cream sales and crime rates

Answer

The correlation between height and weight in a sample of adults

Answer

The correlation between age and income in a sample of workers

Answer

The correlation between GPA and SAT scores

Question 15

How can confounding variables affect the correlation between two variables?

Accepted Answer

All of the above

Answer

By creating a false correlation

Answer

By reversing the direction of the correlation

Answer

By reducing the strength of the correlation

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