Practice Quiz Chapter 13

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. Studies have shown that marriage, an achieved status, means a wage premium, especially for the married male. Which of the following selections is not a reason why this is the case according to social scientists?

a) People can specialize within a couple so that the higher earning partner can devote more time to working for pay correct incorrect

b) Selection bias is a reason for the wage premium because higher-earners attract marriage partners more easily than low-earners correct incorrect

c) Married workers are perceived by employers as more dependable by employers, so they are paid more to retain them correct incorrect

d) Married people tend to drink less than non-married people and hence are seen as more dependable by employers who pay more to retain them correct incorrect

e) People can specialize within a couple so that the lower-earning partner can focus on caring for any kids correct incorrect

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. Which one of the following statements about nested regressions is not true?

a) In order for two or more regressions to be considered nested, they must have the same independent variable and each subsequent regression must add new dependent variables without removing any of the previous dependent variables correct incorrect

b) In order for two or more regressions to be considered nested, they must have the same dependent variable and each subsequent regression must add new independent variables without removing any of the previous independent variables correct incorrect

c) They are useful for understanding how controlling for additional characteristics changes the relationship between each independent variable and the dependent variable correct incorrect

d) Researchers use nested regression to assess how the partial slope coefficient of each independent variable changes as additional variables or groups of variables are accounted for correct incorrect

e) Researchers generate a series of linear regressions that use the same dependent variable and add more and more independent variables each time correct incorrect

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. Most statistical software allows researchers to add independent variables to a regression in blocks. Which of the following statements about this process is not accurate?

a) Doing so allows researchers to determine how a group of variables is associated with the dependent variable correct incorrect

b) Makes it possible for researchers to explicitly link their regression model to theoretical models correct incorrect

c) In nested regression with two blocks, one set of regression coefficients is calculated as though the variables in the first block are the only independent variables in the regression correct incorrect

d) In nested regression with two blocks, one set of regression coefficients is calculated as though the variables in the first block are the only dependent variables in the regression correct incorrect

e) In nested regression the second set of regression coefficients is calculated using the independent variables in both the first and second blocks correct incorrect

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. Why is the parsimonious regression model known as the simplest plausible regression model?

a) Because it uses the fewest independent variables correct incorrect

b) Because it uses the fewest dependent variables correct incorrect

c) It uses theoretically meaningful dependent variables correct incorrect

d) It efficiently predicts the value of the dependent variable without any inapplicable independent variables correct incorrect

e) Because it uses the fewest nested regressions correct incorrect

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. One of the following selections is not something researchers must consider when selecting an independent variable – which one is it?

a) When theoretically relevant variables are not available, researchers must carry on without them or available substitutes correct incorrect

b) Selecting independent variables should always be based on the most current knowledge about the predictors of a dependent variable correct incorrect

c) When theoretically relevant variables are not available, researchers must substitute one or more less relevant ones correct incorrect

d) Sometimes researchers must limit the number of independent variables they use in a regression because there aren't enough cases to support more complex models correct incorrect

e) Selecting independent variables should always be based on the most current theories about the predictors of a dependent variable correct incorrect

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. R2 increases whenever any independent variable is added to a linear regression model, a feature that makes it less useful for deciding whether to add an independent variable to a linear regression model. What do researchers use to mitigate this drawback?

a) Re-adjusted R2 correct incorrect

b) Adjusted R2 correct incorrect

c) Parsimonious equations correct incorrect

d) Pre-adjusted R2 correct incorrect

e) Modified R2 correct incorrect

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. Calculate the adjusted R2 using the following information R2 equals 0.56, n equals 214 and k equals 11. Given this information, what is the adjusted R2?

a) 5.36 correct incorrect

b) 0.0536 correct incorrect

c) 0.536 correct incorrect

d) 0.00536 correct incorrect

e) 536 correct incorrect

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. Calculate the adjusted R2 using the following information R2 equals 0.46, n equals 544 and k equals 31. Given this information, what is the adjusted R2?

a) 0.427 correct incorrect

b) 0.0427 correct incorrect

c) 0.00427 correct incorrect

d) 4.27 correct incorrect

e) 427 correct incorrect

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. What happens to the adjusted R2 when a new independent variable is added to a regression?

a) It will double correct incorrect

b) It decreases if it is a good predictor correct incorrect

c) It will stay the same correct incorrect

d) It increases if it is a poor predictor correct incorrect

e) It either increases or decreases depending on whether the added variable is a good predictor of the dependent variable correct incorrect

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. What should researchers do when an independent variable does not improve the overall model fit?

a) Include the variable only if it is correlated to at least two other independent variables correct incorrect

b) Include the variable only if it is correlated to another independent variable correct incorrect

c) Run the regression equation again correct incorrect

d) If it is theoretically important, do not include the variable correct incorrect

e) If it is theoretically important, include the variable anyway correct incorrect

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. What is the simplest way to assess the collinearity among the independent variables in a regression?

a) Find the Pearson's correlation between each of the dependent variables correct incorrect

b) Find the Pearson's correlation between each of the independent variables correct incorrect

c) Calculate the adjusted R2 correct incorrect

d) Only use dummy variables in the regression model correct incorrect

e) Not worry about it if the collinearity is greater than 0.7 correct incorrect

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. Which one of the following statements about tolerance is not valid?

a) It is a measure of how much variation within each independent variable is not predicted by the other independent variables in the regression correct incorrect

b) It provides information about how much of the variation in each independent variable is unique to that variable and cannot be explained by the other independent variables in the regression correct incorrect

c) Tolerance ranges from 0 to 1 correct incorrect

d) A tolerance of less than 0.1 suggests that there may be a collinearity problem correct incorrect

e) A tolerance of less than 0.1 suggests that there may not be a collinearity problem correct incorrect

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. How do researchers calculate tolerance?

a) Using the VIF correct incorrect

b) With an alternative linear regression that is produced where the variable that the tolerance is being obtained for is used as an independent variable and the remainder of the independent variables are used as dependent ones correct incorrect

c) With an alternative linear regression that is produced where the variable that the tolerance is being obtained for is used as the dependent variable and the remainder of the independent variables are used as such correct incorrect

d) With collinearity equations correct incorrect

e) With parsimonious calculations correct incorrect

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Calculate the tolerance for the variable age if the R2 for the variable is equal to 0.484.

a) 0.516 correct incorrect

b) 0.00516 correct incorrect

c) 5.16 correct incorrect

d) 0.0516 correct incorrect

e) 0.000516 correct incorrect

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. Calculate the VIF for the age variable using the tolerance calculated in the question above. What is the VIF?

a) 0.1937 correct incorrect

b) 0.01937 correct incorrect

c) 19.37 correct incorrect

d) 0.001937 correct incorrect

e) 1.937 correct incorrect

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. When there is a problem of collinearity, which one of the following selections is not a solution to this issue?

a) Omit one of the collinear variables from the regression correct incorrect

b) Pearson's correlation correct incorrect

c) VIF correct incorrect

d) Tolerance correct incorrect

e) Collinear adjustments correct incorrect

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. One of the following statements about residuals is not true – which one is it?

a) The ideal value of a residual is 0, but such values rarely occur correct incorrect

b) Assess the size of residuals – are they outliers and if so how do they affect the regression coefficients correct incorrect

c) Linear regression rests on the notion that residuals are normally distributed correct incorrect

d) The easiest way to assess whether regression residuals are normally distributed is by graphing them in a histogram with a normal curve superimposed on it correct incorrect

e) Linear regression rests on the notion that residuals are not normally distributed correct incorrect

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. What is a Q-Q plot?

a) A histogram with a normal distribution graphed upon it correct incorrect

b) Special type of scatterplot that is used to assess whether the values on a variable could plausibly be randomly selected from a normal distribution correct incorrect

c) Special type of scatterplot that is used to assess whether the values on a variable could plausibly be randomly selected from a non-normal distribution correct incorrect

d) A bar graph of residuals correct incorrect

e) A special type of pie graph of residuals correct incorrect

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. One of the following statements about Q-Q plots is not true– which one is it?

a) In each Q-Q plot the observed values are plotted on the horizontal axis correct incorrect

b) In each Q-Q plot the values from corresponding quantile of a normal distribution are plotted on the vertical axis correct incorrect

c)The Q-Q plot for a left-skewed variable shows an upward curve at the ends of the normal distribution correct incorrect

d) The Q-Q plot for a right-skewed variable shows a downward curve at the ends of the normal distribution, indicating the variables are not normally distributed correct incorrect

e) The Q-Q plot for a right-skewed variable shows a downward curve at the ends of the normal distribution, indicating the variables are normally distributed correct incorrect

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. Calculate the tolerance for the variable age if the R2 for the variable is equal to 0.274.

a) 0.616 correct incorrect

b) 0.00726 correct incorrect

c) 7.26 correct incorrect

d) 0.0616 correct incorrect

e) 0.726 correct incorrect

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. Ascribed status refers to the status someone is assigned at birth whereas achieved status is attained through individual effort, according to Ralph Linton.

a) True correct incorrect

b) False correct incorrect

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. Social scientists have not presented a substantial body of evidence to refute the idea that the Canadian labour market is a meritocracy.

a) True correct incorrect

b) False correct incorrect

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. One useful feature of nested regression is that cases that are missing information on any independent variable, in any block, are omitted from the start.

a) True correct incorrect

b) False correct incorrect

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. Whenever you compare the R2 of nested regressions, the results can change depending on which order the blocks of independent variables are entered in.

a) True correct incorrect

b) False correct incorrect

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. Social scientists strive to build regression models that accurately reflect how individual characteristics and social processes influence people's lives.

a) True correct incorrect

b) False correct incorrect

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. Parsimonious regression models are the most complex, plausible regression models possible.

a) True correct incorrect

b) False correct incorrect

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. R2 will always increase when a new independent variable is added to a regression model.

a) True correct incorrect

b) False correct incorrect

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. Adjusted R2 does not compensate for the fact R2 doesn't distinguish between whether an independent variable is a good predictor or a bad predictor of the dependent variable.

a) True correct incorrect

b) False correct incorrect

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. Adjusted R2 invokes a penalty when independent variables that are poor predictors are added to the regression.

a) True correct incorrect

b) False correct incorrect

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. It generally is not an issue if the independent variables in a regression model are highly correlated with one another.

a) True correct incorrect

b) False correct incorrect

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. One of the main features of multiple linear regression is that it estimates the unique relationship between each independent variable and the dependent variable while controlling for the influence of the other independent variables.

a) True correct incorrect

b) False correct incorrect

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. When there is a strong correlation between two independent variables used in a regression, it is difficult to determine how much of the variation in the dependent variable is attributable to each variable alone.

a) True correct incorrect

b) False correct incorrect

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. Researchers typically utilize calculations for tolerance and VIF if there is a correlation between independent variables in a regression that is less than 0.6 in value.

a) True correct incorrect

b) False correct incorrect

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. Tolerance shows how much of the variation within each independent variable is not predicted by the other independent variables in the regression.

a) True correct incorrect

b) False correct incorrect

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. The (unadjusted) R2 of the alternative linear regression shows how much of the variation in the variable of interest can be explained by the other independent variables in the original regression.

a) True correct incorrect

b) False correct incorrect

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. The VIF provides information about how much the variance of a slope coefficient is likely to be inflated because of an independent variable is correlated with the other independent variables in a regression.

a) True correct incorrect

b) False correct incorrect

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. When the variance of a slope coefficient is inflated, its standard error is not inflated.

a) True correct incorrect

b) False correct incorrect

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. VIFs greater than 10 suggest that there may be a collinearity problem, and one or more variables should be omitted from the regression.

a) True correct incorrect

b) False correct incorrect

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. Researchers' decisions about which independent variables to keep and which to omit are usually based on their judgement about which variable provides the best measure of the social phenomenon they are trying to mode in the regression.

a) True correct incorrect

b) False correct incorrect

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. Q-Q plots assess whether values on a variable could be plausibly randomly selected from a normal distribution by comparing two sets of quantiles, one calculated using the observed data and the second calculated using a perfect normal distribution.

a) True correct incorrect

b) False correct incorrect