dummy Flashcards
A model uses average household income as the dependent variable and county as
the independent variable.
All 120 Kentucky counties are included and modeled using dummy variables.
How many dummy variables will be necessary?
a. 119
b. 120
c. 121
d. 122
a
The number of dummy variables representing a qualitative variable should be
______.
a. one less than the number of categories of the variable
b. two less than the number of categories of the variable
c. the same number as the number of categories of the variable
d. None of these choices is correct.
a
There are 7 dummy variables in a regression equation that represent the states that
survey respondents live in. How many states can we make inferences about from
this regression equation?
a. 5
b. 6
c. 7
d. 8
d
What is one advantage of using dummy variables?
a. They can take any possible value, making it easier to work with
b. They are simpler to add to your model than other variables.
c. They allow you to capture qualitative measures.
d. They have no advantage over other variables
c
Dummy variables are used to transform a ____ variable into a ____
variable.
a. Quantitative; qualitative
b. Qualitative; quantitative
c. Qualitative; categorical
d. Quantitative; categorical
b
Suppose that we have a qualitative variable Month with categories:
January, February, etc.
How many dummy variables are needed to describe Month?
a) 12
b) 11
c) 10
d) 9
b
The model Y = β0 + β1 X1 + β2 D + β3 X1D + ε is an example of a ________.
a) simple linear regression model
b) linear regression model with only a dummy variable
c) linear regression model with a dummy variable and quantitative variable
d) linear regression model with a dummy variable, a quantitative variable,
and an interaction variable
d
Consider the following regression model:
Humidity = β0 + β1 Temperature + β2 Spring + β3 Summer + β4 Fall + β5 Rain + ε,
Where Spring, Summer, and Fall are the dummy variables, and the dummy variable
Rain is defined as Rain = 1 if rainy day, Rain = 0 otherwise.
Assuming the same temperature and precipitation condition, what is the difference
between the predicted humidity for summer and winter days?
a) β0 + β1 + β5
b) β0 + β3 + β5
c) β3
d) β0 + β5
c
Which of the following would most likely be considered a dummy
variable?
A. Temperature
B. Country of origin
C. Height
D. Speed of a car
b
What do we call variables coded as “0” or “1” in regression
equations?
A. Dummy variables
B. Categorical variables
C. Qualitative variables
D. All of the above
d
Whether an independent dummy variable takes the value “0” or
“1” affects which of the following in a simple regression equation?
A. The response variable
B. Intercept
C. Error term
D. None of the above
b
If a regression equation includes 3 dummy variables for nationality,
how many different nationalities can we make inferences about
from this regression equation?
A. 2
B. 3
C. 4
D. 5
c
