LS 15 PHELAN UCLA FINAL EXAM 2024 NEWEST
COMPLETE 200 QUESTIONS WITH DETAILED VERIFIED
ANSWERS (100% CORRECT) /ALREADY GRADED A+
If the correlations between y and each independent variable is strong, it is
reasonable to consider multiple regression analysis. - ANSWER: True
True or false:
y = β0 + β1x1 + β2x2 + ε
is a multiple regression model to predict y on the basis of two independent variables.
- ANSWER: True
In the multiple regression model having two independent variables, the mean level
μy = β0 + β1x1 + β2x2 is represented graphically as ______. - ANSWER: a plane
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β2 interpreted? -
ANSWER: The mean change in y associated with a one-unit increase in x2
The least squares prediction equation can be used to estimate the mean value of the
dependent variable and _____ - ANSWER: to predict an individual value of the
dependent variable.
Before considering a multiple regression analysis, what should be examined? -
ANSWER: The correlations between y and each independent variable.
Plots of y versus each independent variable.
Suppose a contractor specializing in installing hardwood floors uses a multiple
regression model to predict the cost of installing a new floor. If he uses the
independent variables x1 = square footage of the room and x2 = number of linear
feet of baseboard installed, what would it mean if he estimated that b0 = 500, b1 =
20, and b2 = 10? - ANSWER: He estimates it will cost $800 more to install flooring in
a 340 sq ft room than in a 300 sq ft room if the rooms use equal amounts of
baseboard.
He estimates it will cost $100 more to do a job using 70 linear feet of baseboard than
to do one using 60 feet, if the rooms are the same size.
In the multiple regression model having ______ independent variables, the mean
level
μy = β0 + β1x1 + β2x2 is represented graphically as a plane - ANSWER: two
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β0 interpreted? -
ANSWER: The mean y value when x1 = 0 and x2 = 0
True or false: When predicting the value of y, given k independent variables, we use
a value of 0 for the error term, ε. - ANSWER: True
, Intuitively, the best point estimates for the regression parameters β0, β1, ..., βk, are
those that ______ - ANSWER: minimize the residuals.
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β1 interpreted -
ANSWER: The mean change in y associated with a one-unit increase in x1
The least squares prediction equation that best fits observed data gives the smallest
possible ______. - ANSWER: SSE
Regression models that use more than one independent variable are called ______
regression models. - ANSWER: multiple
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β0 interpreted? -
ANSWER: The mean y value when x1 = 0 and x2 = 0
True or false:
y = β0 + β1x1 + β2x2 + ε
is a multiple regression model to predict y on the basis of two independent variables.
- ANSWER: True
Multiple regression models that use _____ independent variable(s). - ANSWER: more
than one
Which of the following is a multiple regression model to predict y on the basis of k >
2 independent variables? - ANSWER: y = β0 + β1x1 + β2x2 +... + βkxk + ε
If the least squares predication equation is found to be ŷŷ = 10 + 2x1 - 3x2, what is
the predicted value of y when x1 = 4 and x2 = 1? - ANSWER: 15
The multiple coefficient of determination, R2, is calculated as ______ - ANSWER:
Explained variation / Total variation
Suppose a multiple regression model using x1 and x2 has R2 = 0.85 and adjusted R2
=0.833. If you add a third variable x3 to the model and discover b3= 0, what happens
to the model and these two quantities? - ANSWER: SSE will not change.
R2 will remain at 0.85.
R2 is the multiple coefficient of determination. What is R? - ANSWER: The multiple
correlation coefficient
Adjusted R2 is preferred in multiple regression because ______ - ANSWER: R2 tends
to overestimate the importance of the independent variables.
True or false: The closer the multiple coefficient of determination is to 1, the better
the model is at predicting y. - ANSWER: True
COMPLETE 200 QUESTIONS WITH DETAILED VERIFIED
ANSWERS (100% CORRECT) /ALREADY GRADED A+
If the correlations between y and each independent variable is strong, it is
reasonable to consider multiple regression analysis. - ANSWER: True
True or false:
y = β0 + β1x1 + β2x2 + ε
is a multiple regression model to predict y on the basis of two independent variables.
- ANSWER: True
In the multiple regression model having two independent variables, the mean level
μy = β0 + β1x1 + β2x2 is represented graphically as ______. - ANSWER: a plane
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β2 interpreted? -
ANSWER: The mean change in y associated with a one-unit increase in x2
The least squares prediction equation can be used to estimate the mean value of the
dependent variable and _____ - ANSWER: to predict an individual value of the
dependent variable.
Before considering a multiple regression analysis, what should be examined? -
ANSWER: The correlations between y and each independent variable.
Plots of y versus each independent variable.
Suppose a contractor specializing in installing hardwood floors uses a multiple
regression model to predict the cost of installing a new floor. If he uses the
independent variables x1 = square footage of the room and x2 = number of linear
feet of baseboard installed, what would it mean if he estimated that b0 = 500, b1 =
20, and b2 = 10? - ANSWER: He estimates it will cost $800 more to install flooring in
a 340 sq ft room than in a 300 sq ft room if the rooms use equal amounts of
baseboard.
He estimates it will cost $100 more to do a job using 70 linear feet of baseboard than
to do one using 60 feet, if the rooms are the same size.
In the multiple regression model having ______ independent variables, the mean
level
μy = β0 + β1x1 + β2x2 is represented graphically as a plane - ANSWER: two
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β0 interpreted? -
ANSWER: The mean y value when x1 = 0 and x2 = 0
True or false: When predicting the value of y, given k independent variables, we use
a value of 0 for the error term, ε. - ANSWER: True
, Intuitively, the best point estimates for the regression parameters β0, β1, ..., βk, are
those that ______ - ANSWER: minimize the residuals.
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β1 interpreted -
ANSWER: The mean change in y associated with a one-unit increase in x1
The least squares prediction equation that best fits observed data gives the smallest
possible ______. - ANSWER: SSE
Regression models that use more than one independent variable are called ______
regression models. - ANSWER: multiple
In the multiple regression model, y = β0 + β1x1 + β2x2 + ε, how is β0 interpreted? -
ANSWER: The mean y value when x1 = 0 and x2 = 0
True or false:
y = β0 + β1x1 + β2x2 + ε
is a multiple regression model to predict y on the basis of two independent variables.
- ANSWER: True
Multiple regression models that use _____ independent variable(s). - ANSWER: more
than one
Which of the following is a multiple regression model to predict y on the basis of k >
2 independent variables? - ANSWER: y = β0 + β1x1 + β2x2 +... + βkxk + ε
If the least squares predication equation is found to be ŷŷ = 10 + 2x1 - 3x2, what is
the predicted value of y when x1 = 4 and x2 = 1? - ANSWER: 15
The multiple coefficient of determination, R2, is calculated as ______ - ANSWER:
Explained variation / Total variation
Suppose a multiple regression model using x1 and x2 has R2 = 0.85 and adjusted R2
=0.833. If you add a third variable x3 to the model and discover b3= 0, what happens
to the model and these two quantities? - ANSWER: SSE will not change.
R2 will remain at 0.85.
R2 is the multiple coefficient of determination. What is R? - ANSWER: The multiple
correlation coefficient
Adjusted R2 is preferred in multiple regression because ______ - ANSWER: R2 tends
to overestimate the importance of the independent variables.
True or false: The closer the multiple coefficient of determination is to 1, the better
the model is at predicting y. - ANSWER: True
