Deck 13: Partial Correlation and

Question 1

After controlling for Z, the partial correlation coefficient is .78. The bivariate Pearson's r between X and Y was only .51. What should the researcher do next?

A) Use
B) Halt the investigation since these results are mathematically impossible
C) Conclude that the relationship between Z and Y is direct
D) Conclude that the relationship between Z and Y is spurious

Answer 1

Use

Question 2

After controlling for Z, a researcher finds evidence of a direct relationship between X and Y. What step should be taken next?

A) Z should become the new independent variable
B) Z should become the new dependent variable
C) Z should be disregarded and a new control variable should be selected
D) Z should be disregarded and a new independent variable should be selected

Answer 2

Z should be disregarded and a new control variable should be selected

Question 3

Partial and multiple correlation require data which are

A) nominal or ordinal
B) ordinal only
C) inferential and bivariate
D) interval-ratio

Answer 3

interval-ratio

Question 4

A researcher examines the relationship between poverty and crime rates for 100 metropolitan areas and finds a zero-order correlation of 0.37. She controls for the percent of families that are headed by single parents and finds a first order partial correlation of 0.06. Which of the following correctly describes this outcome? This is a ______ relationship

A) direct
B) statistically significant
C) spurious
D) interactive

Question 5

A Pearson's r calculated for the bivariate relationship between X and Y is .50. After controlling for Z, the partial correlation coefficient is .49. This outcome would be evidence of a(n) _____________ relationship between X and Y.

A) direct
B) spurious
C) interactive
D) negative

Question 6

After controlling for Z, a researcher finds evidence of a spurious relationship between X and Y. What step should be taken next?

A) Z should become the new independent variable
B) Z should become the new dependent variable
C) Z should be disregarded and a new control variable should be selected
D) Z should be disregarded and a new independent variable should be selected

Question 7

Which of the following would be consistent with a causal model in which X and Z had independent and uncorrelated causal effects on Y?

A) Pearson's r is .37, partial correlation coefficient is .36
B) Pearson's r is .30, partial correlation coefficient is .50
C) Pearson's r is -.10, partial correlation coefficient is -.01
D) Pearson's r is -.41 partial correlation coefficient is .00

Question 8

After controlling for Z, the partial correlation coefficient is .78. The bivariate Pearson's r between X and Y was only .51. Which interpretation is consistent with these results?

A) None, these results are mathematically impossible.
B) There is a spurious relationship between X and Y
C) X and Z are both caused by Y
D) X and Z are separate, uncorrelated causes of Y

Question 9

Partial and multiple correlation are based on

A) bivariate tables
B) random sampling
C) the Analysis of Variance
D) Pearson's r

Question 10

The 'first-order' partial correlation coefficient measures

A) the bivariate relationship between X and Y
B) the relationship between the dependent and control variables
C) the bivariate relationship after controlling for the third variable
D) the bivariate relationship after controlling for the fourth variable

Question 11

Which of the following would be consistent with a spurious relationship between X and Y?

A) Pearson's r is .37, partial correlation coefficient is .36
B) Pearson's r is .78, partial correlation coefficient is .30
C) Pearson's r is -.10, partial correlation coefficient is -.15
D) Pearson's r is .00, partial correlation coefficient is .00

Question 12

After controlling for Z, the partial correlation coefficient between X and Y is the same value as the bivariate Pearson's r. This pattern would be taken as evidence of

A) a direct relationship between X and Y
B) a spurious relationship between X and Z
C) interaction between X, Y, and Z
D) an intervening relationship between X and Y, interaction between X and Z

Question 13

A researcher examines the relationship between poverty and crime rates for 100 metropolitan areas and finds a zero-order correlation of 0.37. She controls for the percent of families that are headed by single parents and finds a first order partial correlation of 0.33. Which of the following correctly describes this outcome? This is a ______ relationship

A) direct
B) statistically significant
C) spurious
D) interactive

Question 14

Partial correlation will detect all of the following relationships among variables except

A) interaction
B) direct relationships
C) spurious relationships
D) intervening relationships

Question 15

An analysis of the relationship between income and education found a correlation of 0.43. After controlling for age, the partial correlation was 0.43. The relationship between income and education seems to be

A) direct
B) spurious
C) intervening
D) interactive

Question 16

When examining a bivariate relationship using Pearson's r, the partial correlation computed while using one control variable is called

A) the first-order partial correlation coefficient
B) the second-order partial correlation coefficient
C) the intervening partial correlation coefficient
D) the

Question 17

The partial correlation coefficient will reveal an interactive relationship between three variables when

A) the partial correlation coefficients drops to zero
B) the partial is greater in value than the zero-order correlation coefficient
C) the partial correlation coefficient is negative
D) none of the above. Partial correlation will not detect interaction

Question 18

The partial correlation coefficient between X and Y after controlling for Z shows a much weaker relationship than the Pearson's r computed for X and Y. This would be taken as evidence of a(n) _____________ relationship between X and Y.

A) direct
B) spurious or intervening
C) interactive
D) positive

Question 19

Which of the following would be consistent with a direct relationship between X and Y?

A) Pearson's r is .17, partial correlation coefficient is .16
B) Pearson's r is .78, partial correlation coefficient is .50
C) Pearson's r is .10, partial correlation coefficient is .20
D) Pearson's r is .00, partial correlation coefficient is .00

Question 20

A Pearson's r calculated for a bivariate relationship is .50. After controlling for Z, the partial correlation coefficient is .07. This outcome would be evidence of a(n) _____________ relationship between X and Y.

A) direct
B) spurious or intervening
C) interactive
D) positive

Question 21

In the least-squares

A) the point where the line crosses the Y axis
B) the combined effects of all independents on the dependent variable
C) the amount of change in Y for a unit change in one independent variable while controlling for all other independent variables
D) the residual effects of the independent after partialling out the effect of the dependent variable

Question 22

If a = 1, b1 = 10, b2 = 10, X1= 2, and X2 = 3, what would the predicted Y score be?

A) 51
B) 26
C) 5
D) 0

Question 23

Standardized partial slopes can be computed by

A) converting all scores to Z scores
B) converting all scores to percentages
C) converting the partial slopes to Z scores
D) taking a percentage of the partial slopes

Question 24

In the multiple regression equation, the partial slopes are represented by the symbol

A) a
B) b*
C) a*
D) b

Question 25

The regression equation for a particular relationship is Y = 10 + (.78) X1 + (-.54) X2. Which conclusion is consistent with this equation?

A) The Y intercept is zero
B) Neither independent variable has an important relationship with Y
C) A value for a (the Y intercept) needs to be calculated before the equation can be interpreted
D) The two independent variables have opposite effects on the dependent variable

Question 26

If a = 17, b1 = 5, b2 = 20, X1= 100, and X2 = 200, what would the predicted Y score be?

A) 17
B) 4,517
C) 101
D) 6,217

Question 27

While unstandardized partial slopes permit predictions of Y in the original units of the variable, standardized partial slopes permit an assessment of

A) the combined effects of the independents
B) the partial effects of the independents
C) the independent effects of the partials
D) the relative importance of the independents

Question 28

A researcher is trying to determine if income (X1) or number of friends (X2) is more important in determining personal happiness (Y). Which of the following would be the most profitable course of action?

A) examine the standardized partial slopes of X1 and X2 on Y
B) examine the unstandardized partial slopes of X1 and X2 on Y
C) compute the partial correlation coefficient for X1 and X2 controlling for Y
D) examine the partial slope of Y on each independent separately

Question 29

One advantage of the technique of

A) combined... independents
B) separate... independents
C) combined... control
D) separate... dependents

Question 30

In the

A) partial slope
B) slope of X and Y
C) beta slope of X and Z
D) Y intercept

Question 31

Standardized partial slopes are also called

A) alpha levels
B) gammas
C) Z scores
D) beta weights

Question 32

A standardized regression equation is stated as: Zy = (.46)Z1 + (.47)Z1. Which conclusion is most consistent with this formula?

A) Z is caused by both X and Y
B) The independents have equally strong relationships with the dependent
C) This is a spurious relationship
D) There is a direct relationship between X and Y after controlling for the effects of Z

Question 33

Which of the following is a correctly stated standardized regression equation?

A) Zy = a - b1*Z1 - b2Z2
B) Zy = a + b1X1 - b2X2
C) Zy = b1*Z1 + b2*Z2
D) Zy = b1*Z1 - b2Z2

Question 34

In regression analysis, the standardized partial slopes are symbolized as

A) b*
B) B
C) b#
D) r*

Question 35

With two independent variables, the least-squares

A) Y = a + bX²
B) Y = a + b + X1 + X²
C) Y = b1X1 + b2X2
D) Y = a + b1X1 + b2X2

Question 36

A researcher wants to predict score on personal happiness (Y) from score on income (X1) and number of friends (X2). Which of the following would be the proper course of action?

A) use the standardized partial slopes of X1 and X2 on Y
B) examine the unstandardized partial slopes of X1 and X2 on Y
C) compute the partial correlation coefficient for X1 and X2 controlling for Y
D) examine the partial slope of Y on each independent separately

Question 37

In the

A) chi square
B) gamma
C) Pearson's r
D) the partial correlation coefficient

Question 38

To investigate the combined effects of several independent variables on a single dependent variable, we use

A) partial correlation and regression
B) bivariate correlation and regression
C) multiple correlation and regression
D) interactive correlation and regression

Question 39

After scores have been standardized, the value of a (the Y-intercept) will always be

A) 1
B) 0
C) b1 - b2
D) R²

Question 40

If the beta-weight of the first independent (X1) is .45 and the beta-weight of the second independent (X2) is -.50, then

A) X1 has a stronger direct effect than X2
B) X2 has a stronger direct effect than X1
C) Y2 must equal zero
D) the

Question 41

Which of the following is not a prerequisite for the use of the techniques of

A) interval-ratio level of measurement
B) linear relationships
C) no interaction among the variables
D) partial slopes less than zero

Question 42

The coefficient of

A) the amount of variation explained by X1 plus the amount of variation explained by X2 after controlling for the effect of X1
B) the amount of variation explained by X1 minus the amount of variation unexplained by X2
C) the total variation in Y minus the amount unexplained by X1 after controlling for X2
D) the sum of all explained and unexplained variation in X1 and X2

Question 43

Under what condition could the coefficient of

A) under no condition. This is mathematically impossible
B) only when all bivariate relationships are negative
C) only when all bivariate relationships are zero
D) only when the relationships are spurious

Question 44

A researcher is examining the effects of income (X1) and number of friends (X2) on personal happiness (Y) and finds an R² of 0.45. Which of the following is a correct interpretation of this result?

A) Money CAN buy happiness
B) Friends are more important than money for happiness
C) Taken together, income and number of friends explain 45% of the variance in happiness
D) Taken together, income and number of friends explain 0.45% of the variance in happiness

Question 45

The text cites an example in which

A) football
B) basketball
C) baseball
D) soccer

Question 46

To the extent that the variables do not meet the assumptions of regression analysis, coefficients and slopes become

A) greater in value
B) lower in value
C) less trustworthy
D) less representative of the population

Question 47

The techniques of

A) the total number of variables is not greater than three
B) the independents are strongly correlated with each other
C) each independent is linearly related with the dependent variable
D) sample size is less than 100

Question 48

The coefficient of

A) the effect of the control variable after removing the independent from the equation
B) essentially the same thing as a partial gamma
C) the combined effects of all independents on the dependent
D) the zero-order relationships after controlling for the independents