Exam 16: Multiple Regression Model Building

arrow
  • Select Tags
search iconSearch Question
flashcardsStudy Flashcards
  • Select Tags

One use of VIF in multiple regression is deciding which variable to include in a model.

(True/False)
4.9/5
(36)

Collinearity is present if the dependent variable is linearly related to one of the explanatory variables.

(True/False)
4.7/5
(35)

The Variance Inflationary Factor (VIF)measures the

(Multiple Choice)
5.0/5
(30)

A certain type of rare gem serves as a status symbol for many of its owners. In theory, for low prices, the demand decreases as the price of the gem increases. However, experts hypothesise that when the gem is valued at very high prices, the demand increases with price due to the status owners believe they gain in obtaining the gem. Thus, the model proposed to best explain the demand for the gem by its price is the quadratic model: Y=B0+B1X+B2X2+εY = B _ { 0 } + B _ { 1 } X + B_ { 2 } X ^ { 2 } + \varepsilon where Y = demand (in thousands) and X = retail price per carat. SUMMARY OUTPUT Regression Statistics Multiple R 0.994 R Square 0.988 Std. Error 12.42 Observations 12 ANOVA df SS MS F Signif F Regression 2 115,145 57,573 373 0.0001 Residual 9 1,388 154 Total 11 116,533 Coeff Std. Error t Stat P -Value Intercept 286.42 9.66 29.64 0.0001 Price -0.31 0.06 -5.14 0.0006 Price Sq 0.000067 0.00007 0.95 0.3647 This model was fit to data collected for a sample of 12 rare gems of this type. A portion of the computer analysis obtained from Microsoft Excel is shown below: -Referring to Instruction 16-1,what is the value of the test statistic for testing whether the quadratic term is necessary in fitting in the response curve relating the demand (Y)and the price (X)?

(Multiple Choice)
4.9/5
(32)

Instruction 16-6 Given below are results from the regression analysis on 40 observations where the dependent variable is the number of weeks a worker is unemployed due to a layoff (Y) and the independent variables are the age of the worker (X1), the number of years of education received (X2), the number of years at the previous job (X3), a dummy variable for marital status (X4: 1 = married, 0 = otherwise), a dummy variable for head of household (X5: 1 = yes, 0 = no) and a dummy variable for management position (X6: 1 = yes, 0 = no). The coefficient of multiple determination (R2j) the regression model using each of the 6 variables Xj as the dependent variable and all other X variables as independent variables are, respectively, 0.2628, 0.1240, 0.2404, 0.3510, 0.3342 and 0.0993. The partial results from best-subset regression are given below: Model R Square Adj. R Square Std. Error 0.4568 0.4116 18.3534 0.4697 0.4091 18.3919 0.4691 0.4084 18.4023 0.4877 0.4123 18.3416 0.4949 0.4030 18.4861 -Referring to Instruction 16-6,the variable X2 should be dropped to remove collinearity.

(True/False)
4.7/5
(33)

A real estate developer wishes to determine how house size (House)is influenced by family income (Income),family size (Size),and education of the head of household (School).House size is measured in hundreds of square metres,income is measured in thousands of dollars and education is in years.The developer randomly selected 50 families and developed a multiple regression model.The business literature involving human capital shows that education influences an individual's annual income.Combined,these may influence family size.With this in mind,what should the real estate developer be particularly concerned with when analysing the multiple regression model?

(Multiple Choice)
4.7/5
(34)

Instruction 16-2 A chemist employed by a pharmaceutical firm has developed a muscle relaxant. She took a sample of 14 people suffering from extreme muscle constriction. She gave each a vial containing a dose (X) of the drug and recorded the time to relief (Y) measured in seconds for each. She fit a quadratic model to this data. The results obtained by Microsoft Excel follow. OUTPU? Regression Statistics Multiple R 0.747 R Square 0.558 Adj. R Square 0.478 Std. Error 863.1 Observations 14 ANOVA df Ss MS F Signif F Regression 2 10,344,797 5,172,399 6.94 0.0110 Residual 11 8,193,929 744,903 Total 13 18,538,726 Coeff Std. Error t stat P -value Intercept 1283.0 352.0 3.65 0.0040 CenDose 25.228 8.631 2.92 0.0140 CenDoseSq 0.8604 0.3722 2.31 0.0410 Note: Adj. R Square = Adjusted R Square; Std. Error = Standard Error -Referring to Instruction 16-2,suppose the chemist decides to use an F test to determine if there is a significant quadratic relationship between time and dose.If she chooses to use a level of significance of 0.05,she would decide that there is a significant curvilinear relationship.

(True/False)
4.8/5
(37)

Instruction 16-6 Given below are results from the regression analysis on 40 observations where the dependent variable is the number of weeks a worker is unemployed due to a layoff (Y) and the independent variables are the age of the worker (X1), the number of years of education received (X2), the number of years at the previous job (X3), a dummy variable for marital status (X4: 1 = married, 0 = otherwise), a dummy variable for head of household (X5: 1 = yes, 0 = no) and a dummy variable for management position (X6: 1 = yes, 0 = no). The coefficient of multiple determination (R2j) the regression model using each of the 6 variables Xj as the dependent variable and all other X variables as independent variables are, respectively, 0.2628, 0.1240, 0.2404, 0.3510, 0.3342 and 0.0993. The partial results from best-subset regression are given below: Model R Square Adj. R Square Std. Error 0.4568 0.4116 18.3534 0.4697 0.4091 18.3919 0.4691 0.4084 18.4023 0.4877 0.4123 18.3416 0.4949 0.4030 18.4861 -Referring to Instruction 16-6,the variable X6 should be dropped to remove collinearity.

(True/False)
4.8/5
(33)

The logarithm transformation can be used

(Multiple Choice)
4.8/5
(33)

Instruction 16-6 Given below are results from the regression analysis on 40 observations where the dependent variable is the number of weeks a worker is unemployed due to a layoff (Y) and the independent variables are the age of the worker (X1), the number of years of education received (X2), the number of years at the previous job (X3), a dummy variable for marital status (X4: 1 = married, 0 = otherwise), a dummy variable for head of household (X5: 1 = yes, 0 = no) and a dummy variable for management position (X6: 1 = yes, 0 = no). The coefficient of multiple determination (R2j) the regression model using each of the 6 variables Xj as the dependent variable and all other X variables as independent variables are, respectively, 0.2628, 0.1240, 0.2404, 0.3510, 0.3342 and 0.0993. The partial results from best-subset regression are given below: Model R Square Adj. R Square Std. Error 0.4568 0.4116 18.3534 0.4697 0.4091 18.3919 0.4691 0.4084 18.4023 0.4877 0.4123 18.3416 0.4949 0.4030 18.4861 -Referring to Instruction 16-6,what is the value of the variance inflationary factor of Manager?

(Short Answer)
4.9/5
(40)

Instruction 16-6 Given below are results from the regression analysis on 40 observations where the dependent variable is the number of weeks a worker is unemployed due to a layoff (Y) and the independent variables are the age of the worker (X1), the number of years of education received (X2), the number of years at the previous job (X3), a dummy variable for marital status (X4: 1 = married, 0 = otherwise), a dummy variable for head of household (X5: 1 = yes, 0 = no) and a dummy variable for management position (X6: 1 = yes, 0 = no). The coefficient of multiple determination (R2j) the regression model using each of the 6 variables Xj as the dependent variable and all other X variables as independent variables are, respectively, 0.2628, 0.1240, 0.2404, 0.3510, 0.3342 and 0.0993. The partial results from best-subset regression are given below: Model R Square Adj. R Square Std. Error 0.4568 0.4116 18.3534 0.4697 0.4091 18.3919 0.4691 0.4084 18.4023 0.4877 0.4123 18.3416 0.4949 0.4030 18.4861 -Referring to Instruction 16-6,what is the value of the Mallow's Cp statistic for the model that includes X1,X3,X5 and X6?

(Short Answer)
4.7/5
(31)

The stepwise regression approach takes into consideration all possible models.

(True/False)
4.8/5
(36)

Instruction 16-2 A chemist employed by a pharmaceutical firm has developed a muscle relaxant. She took a sample of 14 people suffering from extreme muscle constriction. She gave each a vial containing a dose (X) of the drug and recorded the time to relief (Y) measured in seconds for each. She fit a quadratic model to this data. The results obtained by Microsoft Excel follow. OUTPU? Regression Statistics Multiple R 0.747 R Square 0.558 Adj. R Square 0.478 Std. Error 863.1 Observations 14 ANOVA df Ss MS F Signif F Regression 2 10,344,797 5,172,399 6.94 0.0110 Residual 11 8,193,929 744,903 Total 13 18,538,726 Coeff Std. Error t stat P -value Intercept 1283.0 352.0 3.65 0.0040 CenDose 25.228 8.631 2.92 0.0140 CenDoseSq 0.8604 0.3722 2.31 0.0410 Note: Adj. R Square = Adjusted R Square; Std. Error = Standard Error -Referring to Instruction 16-2,suppose the chemist decides to use a t test to determine if there is a significant difference between a linear model and a quadratic model that includes a linear term.If she used a level of significance of 0.01,she would decide that the linear model is sufficient.

(True/False)
4.7/5
(37)

A microeconomist wants to determine how corporate sales are influenced by capital and wage spending by companies.She proceeds to randomly select 26 large corporations and records information in millions of dollars.A statistical analyst discovers that capital spending by corporations has a significant inverse relationship with wage spending.What should the microeconomist who developed this multiple regression model be particularly concerned with?

(Multiple Choice)
4.8/5
(30)

It is unnecessary to examine several alternative models using best-subsets regression.

(True/False)
4.8/5
(30)

Instruction 16-6 Given below are results from the regression analysis on 40 observations where the dependent variable is the number of weeks a worker is unemployed due to a layoff (Y) and the independent variables are the age of the worker (X1), the number of years of education received (X2), the number of years at the previous job (X3), a dummy variable for marital status (X4: 1 = married, 0 = otherwise), a dummy variable for head of household (X5: 1 = yes, 0 = no) and a dummy variable for management position (X6: 1 = yes, 0 = no). The coefficient of multiple determination (R2j) the regression model using each of the 6 variables Xj as the dependent variable and all other X variables as independent variables are, respectively, 0.2628, 0.1240, 0.2404, 0.3510, 0.3342 and 0.0993. The partial results from best-subset regression are given below: Model R Square Adj. R Square Std. Error 0.4568 0.4116 18.3534 0.4697 0.4091 18.3919 0.4691 0.4084 18.4023 0.4877 0.4123 18.3416 0.4949 0.4030 18.4861 -Referring to Instruction 16-6,the model that includes X1,X5 and X6 should be selected using the adjusted r2 statistic.

(True/False)
4.8/5
(46)

Instruction 16-2 A chemist employed by a pharmaceutical firm has developed a muscle relaxant. She took a sample of 14 people suffering from extreme muscle constriction. She gave each a vial containing a dose (X) of the drug and recorded the time to relief (Y) measured in seconds for each. She fit a quadratic model to this data. The results obtained by Microsoft Excel follow. OUTPU? Regression Statistics Multiple R 0.747 R Square 0.558 Adj. R Square 0.478 Std. Error 863.1 Observations 14 ANOVA df Ss MS F Signif F Regression 2 10,344,797 5,172,399 6.94 0.0110 Residual 11 8,193,929 744,903 Total 13 18,538,726 Coeff Std. Error t stat P -value Intercept 1283.0 352.0 3.65 0.0040 CenDose 25.228 8.631 2.92 0.0140 CenDoseSq 0.8604 0.3722 2.31 0.0410 Note: Adj. R Square = Adjusted R Square; Std. Error = Standard Error -Referring to Instruction 16-2,the prediction of time to relief for a person receiving a dose of the drug 10 units above the average dose is _______.

(Short Answer)
4.9/5
(31)

Instruction 16-6 Given below are results from the regression analysis on 40 observations where the dependent variable is the number of weeks a worker is unemployed due to a layoff (Y) and the independent variables are the age of the worker (X1), the number of years of education received (X2), the number of years at the previous job (X3), a dummy variable for marital status (X4: 1 = married, 0 = otherwise), a dummy variable for head of household (X5: 1 = yes, 0 = no) and a dummy variable for management position (X6: 1 = yes, 0 = no). The coefficient of multiple determination (R2j) the regression model using each of the 6 variables Xj as the dependent variable and all other X variables as independent variables are, respectively, 0.2628, 0.1240, 0.2404, 0.3510, 0.3342 and 0.0993. The partial results from best-subset regression are given below: Model R Square Adj. R Square Std. Error 0.4568 0.4116 18.3534 0.4697 0.4091 18.3919 0.4691 0.4084 18.4023 0.4877 0.4123 18.3416 0.4949 0.4030 18.4861 -Referring to Instruction 16-6,what is the value of the Mallow's Cp statistic for the model that includes X1,X2,X5 and X6?

(Short Answer)
4.7/5
(38)

If a person uses a multiple regression model when it is clear that model assumptions have not been met,this is a violation of ethics.

(True/False)
4.8/5
(29)

Which of the following will NOT change a nonlinear model into a linear model?

(Multiple Choice)
4.8/5
(34)
Showing 21 - 40 of 93
close modal

Filters

  • Essay(0)
  • Multiple Choice(0)
  • Short Answer(0)
  • True False(0)
  • Matching(0)