ISYE6414 Midterm 2
What is the formula for the logit function? - CORRECT ANSWER-ln(p/1-p)
The interpretation of the regression coefficients in logistic regression is the same as for
standard linear regression assuming normality. - CORRECT ANSWER-False
The estimation of the regression coefficients is based on what? - CORRECT ANSWER-
maximum likelihood estimation
We can derive exact (close form expression) estimates for the regression coefficients. -
CORRECT ANSWER-False
In logistic regression, the estimations of the regression coefficients is based on
minimizing the sum of least squares. - CORRECT ANSWER-False
The function to perform logistic regression in R is what? - CORRECT ANSWER-glm(...,
family="binomial")
In R, the input of the response variable is exactly the same if the binary response data
are with or without replications. - CORRECT ANSWER-False
In R, we can obtain both the estimates and the standard deviations of the estimates for
the regression coefficients for a logistic regression model. - CORRECT ANSWER-True
In logistic regression, the sampling distribution of the regression coefficient is
approximate. - CORRECT ANSWER-True
Logistic regression requires large sample data for making accurate statistical
inferences. - CORRECT ANSWER-True
In logistic regression, a normal sampling distribution is used instead of a t-distribution
for statistical inference. - CORRECT ANSWER-True
In logistic regression, the hypothesis test for subsets of coefficients is a goodness of fit
test. - CORRECT ANSWER-False
In logistic regression, the hypothesis test for subsets of coefficients is approximate; it
relies on large sample size. - CORRECT ANSWER-True
, In logistic regression, we can use the partial F test for testing whether a subset of
coefficients are all zero. - CORRECT ANSWER-False
What is used to quantify outliers? - CORRECT ANSWER-Cook's distance
How much all the values in the model change when the ith value is removed is known
as what? - CORRECT ANSWER-Cook's distance
Cooks distance that should be investigated. - CORRECT ANSWER-D_i > 4/n or D_i > 1
or Large D
The proportion of variability in Y than can be explained by the predictor variables. -
CORRECT ANSWER-R-Squared
Model variables used to account for selection bias. - CORRECT ANSWER-Controlling
factors
Continuous variables are converted to ________ when there is a distinct gap in a
variable distribution. - CORRECT ANSWER-Indicator variable
The number of degrees of freedom for a T test for the statistical significance of a MLR
coefficient? - CORRECT ANSWER-n-p-1
When the regression model has a high F value/low p-value. - CORRECT ANSWER-At
least one variable has explainitory power on the response variable.
When testing subsets of coefficients using anova command. - CORRECT ANSWER-
order matters
When can "year" be used as a qualitative variable? - CORRECT ANSWER-If the
variable is not very granular
Used to evaluate the relationship between any two qualitative variables. - CORRECT
ANSWER-Pearson Chi-squared test
A command needed prior to running a pearson chi-squared test of qualitative variables.
- CORRECT ANSWER-table
What should you do when you have a high number of predicting variables due to a large
number of categorical variables resulting in numerous dummy variables. - CORRECT
ANSWER-Reduce the dummy variables into groups
Which category does R choose as the baseline label when creating dummy variables
with as.factor() - CORRECT ANSWER-The first
What is the formula for the logit function? - CORRECT ANSWER-ln(p/1-p)
The interpretation of the regression coefficients in logistic regression is the same as for
standard linear regression assuming normality. - CORRECT ANSWER-False
The estimation of the regression coefficients is based on what? - CORRECT ANSWER-
maximum likelihood estimation
We can derive exact (close form expression) estimates for the regression coefficients. -
CORRECT ANSWER-False
In logistic regression, the estimations of the regression coefficients is based on
minimizing the sum of least squares. - CORRECT ANSWER-False
The function to perform logistic regression in R is what? - CORRECT ANSWER-glm(...,
family="binomial")
In R, the input of the response variable is exactly the same if the binary response data
are with or without replications. - CORRECT ANSWER-False
In R, we can obtain both the estimates and the standard deviations of the estimates for
the regression coefficients for a logistic regression model. - CORRECT ANSWER-True
In logistic regression, the sampling distribution of the regression coefficient is
approximate. - CORRECT ANSWER-True
Logistic regression requires large sample data for making accurate statistical
inferences. - CORRECT ANSWER-True
In logistic regression, a normal sampling distribution is used instead of a t-distribution
for statistical inference. - CORRECT ANSWER-True
In logistic regression, the hypothesis test for subsets of coefficients is a goodness of fit
test. - CORRECT ANSWER-False
In logistic regression, the hypothesis test for subsets of coefficients is approximate; it
relies on large sample size. - CORRECT ANSWER-True
, In logistic regression, we can use the partial F test for testing whether a subset of
coefficients are all zero. - CORRECT ANSWER-False
What is used to quantify outliers? - CORRECT ANSWER-Cook's distance
How much all the values in the model change when the ith value is removed is known
as what? - CORRECT ANSWER-Cook's distance
Cooks distance that should be investigated. - CORRECT ANSWER-D_i > 4/n or D_i > 1
or Large D
The proportion of variability in Y than can be explained by the predictor variables. -
CORRECT ANSWER-R-Squared
Model variables used to account for selection bias. - CORRECT ANSWER-Controlling
factors
Continuous variables are converted to ________ when there is a distinct gap in a
variable distribution. - CORRECT ANSWER-Indicator variable
The number of degrees of freedom for a T test for the statistical significance of a MLR
coefficient? - CORRECT ANSWER-n-p-1
When the regression model has a high F value/low p-value. - CORRECT ANSWER-At
least one variable has explainitory power on the response variable.
When testing subsets of coefficients using anova command. - CORRECT ANSWER-
order matters
When can "year" be used as a qualitative variable? - CORRECT ANSWER-If the
variable is not very granular
Used to evaluate the relationship between any two qualitative variables. - CORRECT
ANSWER-Pearson Chi-squared test
A command needed prior to running a pearson chi-squared test of qualitative variables.
- CORRECT ANSWER-table
What should you do when you have a high number of predicting variables due to a large
number of categorical variables resulting in numerous dummy variables. - CORRECT
ANSWER-Reduce the dummy variables into groups
Which category does R choose as the baseline label when creating dummy variables
with as.factor() - CORRECT ANSWER-The first
