Podcast
Questions and Answers
Which of the following is true about retaining explanatory variables in a regression model?
Which of the following is true about retaining explanatory variables in a regression model?
- Only the least fundamental explanatory variables should be retained in the model
- Only the most fundamental explanatory variables should be retained in the model (correct)
- The selection of explanatory variables does not affect the model
- All explanatory variables should be retained in the model
When should indicator variables representing a qualitative predictor variable be kept together as a group in a regression model?
When should indicator variables representing a qualitative predictor variable be kept together as a group in a regression model?
- When a subset of indicator variables is better according to the criterion employed (correct)
- When the qualitative variable is not significant
- When all indicator variables are significant
- When the indicator variables are not significant
In a regression model, if second-order terms or interaction terms are present, what is the preferred order of including the terms?
In a regression model, if second-order terms or interaction terms are present, what is the preferred order of including the terms?
- First-order terms should be included after second-order terms
- Interaction terms should be included before first-order terms
- First-order terms should be included before second-order terms (correct)
- Second-order terms should be included before first-order terms
Which method of variable selection is a combination of forward and backward procedures?
Which method of variable selection is a combination of forward and backward procedures?
Which model has the largest adjusted coefficient of determination (Ra2) and the fewest number of independent variables?
Which model has the largest adjusted coefficient of determination (Ra2) and the fewest number of independent variables?
Which method of variable selection starts with all independent variables in the model and then deletes variables one at a time using a partial F-test until all remaining variables produce a significant F statistic?
Which method of variable selection starts with all independent variables in the model and then deletes variables one at a time using a partial F-test until all remaining variables produce a significant F statistic?
Which method of variable selection inserts independent variables one at a time until a satisfactory regression equation is found, starting with the variable that has the highest correlation with the response variable?
Which method of variable selection inserts independent variables one at a time until a satisfactory regression equation is found, starting with the variable that has the highest correlation with the response variable?
Which criterion is used to find the point where adding more X variables is not worthwhile because it leads to a very small increase in Rp2?
Which criterion is used to find the point where adding more X variables is not worthwhile because it leads to a very small increase in Rp2?
Which criterion penalizes models with large numbers of predictors and favors more parsimonious models?
Which criterion penalizes models with large numbers of predictors and favors more parsimonious models?
Which criterion measures the total mean squared error of the fitted values for each subset regression model?
Which criterion measures the total mean squared error of the fitted values for each subset regression model?
Which criterion is a measure of how well the use of the fitted values for a subset model can predict the observed responses?
Which criterion is a measure of how well the use of the fitted values for a subset model can predict the observed responses?
Which of the following is NOT one of the objectives of multiple linear regression?
Which of the following is NOT one of the objectives of multiple linear regression?
Which criterion is equivalent to using the error sum of squares (SSEp) as the criterion for selecting subsets of X variables?
Which criterion is equivalent to using the error sum of squares (SSEp) as the criterion for selecting subsets of X variables?
Which procedure aims to identify a small group of regression models that are considered 'good' according to a specified criterion?
Which procedure aims to identify a small group of regression models that are considered 'good' according to a specified criterion?
Which criterion is used to identify several 'good' subsets of X variables based on a high coefficient of multiple determination R2?
Which criterion is used to identify several 'good' subsets of X variables based on a high coefficient of multiple determination R2?
Which criterion is equivalent to using the error sum of squares SSEp as the criterion for selecting 'good' subsets of X variables?
Which criterion is equivalent to using the error sum of squares SSEp as the criterion for selecting 'good' subsets of X variables?
Which procedure aims to identify a small group of regression models that are considered 'good' according to a specified criterion, leading to the selection of the final regression model to be employed?
Which procedure aims to identify a small group of regression models that are considered 'good' according to a specified criterion, leading to the selection of the final regression model to be employed?
Which criterion measures the total mean squared error of the fitted values for each subset regression model?
Which criterion measures the total mean squared error of the fitted values for each subset regression model?
When should indicator variables representing a qualitative predictor variable be kept together as a group in a regression model?
When should indicator variables representing a qualitative predictor variable be kept together as a group in a regression model?
Which criterion penalizes models with large numbers of predictors and favors more parsimonious models?
Which criterion penalizes models with large numbers of predictors and favors more parsimonious models?
Which method of variable selection inserts independent variables one at a time until a satisfactory regression equation is found, starting with the variable that has the highest correlation with the response variable?
Which method of variable selection inserts independent variables one at a time until a satisfactory regression equation is found, starting with the variable that has the highest correlation with the response variable?
Which of the following is a method of validating a regression model?
Which of the following is a method of validating a regression model?
When should indicator variables representing a qualitative predictor variable be kept together as a group in a regression model?
When should indicator variables representing a qualitative predictor variable be kept together as a group in a regression model?
In a regression model, if second-order terms or interaction terms are present, what is the preferred order of including the terms?
In a regression model, if second-order terms or interaction terms are present, what is the preferred order of including the terms?
Which of the following is true about the forward selection method of variable selection?
Which of the following is true about the forward selection method of variable selection?
Which criterion is used to select subsets of X variables in the all-possible-regressions procedure?
Which criterion is used to select subsets of X variables in the all-possible-regressions procedure?
Which method of variable selection is a combination of forward and backward procedures?
Which method of variable selection is a combination of forward and backward procedures?
Which model has the largest adjusted coefficient of determination (Ra2) and the fewest number of independent variables?
Which model has the largest adjusted coefficient of determination (Ra2) and the fewest number of independent variables?
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