2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Midterm Exam
Due Feb 10 at 3:20pm Points 100 Questions 40
Available Feb 10 at 2pm – Feb 10 at 3:20pm about 1 hour Time Limit 80 Minutes
Copyright By PowCoder代写 加微信 powcoder
Instructions
You have exactly 80 minutes to complete this exam. Each question is worth 2.5 points. Question and answer order is randomized. Only one question can be viewed at a time and backtracking is NOT allowed. Once you have submitted an answer, you will not be able to change it later. You will not be able to view the previous question. Unless otherwise specified, refers to the OLS estimator.
This quiz was locked Feb 10 at 3:20pm.
Attempt History
Attempt Time Score
LATEST Attempt 1 69 minutes 50 out of 100
Score for this quiz: 50 out of 100 Submitted Feb 10 at 3:11pm This attempt took 69 minutes.
u Answered
Question 1
0 / 2.5 pts
Assume you want to study how education affects income, so you plan to collect data for a group of people and regress each individual’s income on his/her education. Which of the following cases is most likely to yield the most precise estimates?
Collect a sample of 100 individuals with years of education ranging from 0-12.
Collect a sample of 500 individuals with years of education equal to 12.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
rrect Answer
Collect a sample of 500 individuals with years of education ranging from 0-12.
Collect a sample of 1000 individuals with years of education equal to 9.
Assume you want to run the following regression for a sample of 500 college students:
denotes an individual’s college GPA, denotes
an individual’s high school GPA, and denotes an individual’s SAT
score. If you want to test the null hypothesis should:
estimate and , and check whether either of the estimators is close to zero.
do a single F-test of .
do one t-test of and one t-test of .
estimate and , and check whether both the estimators are close to zero.
u Answered
rrect Answer
Question 2
0 / 2.5 pts
Question 3
2.5 / 2.5 pts
White’s robust standard errors can be used in cases when
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 4
2.5 / 2.5 pts
The error term in a regression equation is said to exhibit homoskedasticty if
if the error term has a value of one given any value of the explanatory variable.
it has the same value for all values of the explanatory variable.
it has the same variance for all values of the explanatory variable. it has zero conditional mean.
we need to decide whether more data will improve the precision of estimation
we need to decide whether to use GLS or FGLS
we know the form of heteroskedasticity and can use GLS
we are unsure about the form of heteroskedasticity or whether it is present at all
Question 5
2.5 / 2.5 pts
Which of these statements is true
heteroskedasticity can be eliminated in repeated samples
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 6
2.5 / 2.5 pts
Assume the true model is regression of on both and
get and . What is the value of
It depends on the variance of It depends on the sample size
. However, you run an OLS for a sample of observations to
omitted variable bias can be eliminated in repeated samples inefficiency can be eliminated in repeated samples homoskedasticity can be eliminated in repeated samples none of these statements are correct
Question 7
0 / 2.5 pts
Assume you are estimating the following model
using a sample of 500 observations.
The OLS estimators for and are and respectively. The residual vector is given by
. We also know that .
If you want to test the null hypothesis , what is your t- statistic?
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
u Answered
rrect Answer
Question 8
2.5 / 2.5 pts
Given covariates , instruments , and dependent variable , the two stages of TSLS estimation are:
Regress Regress Regress Regress
on to get ; then regress on on to get ; then regress on
on , get ; then regress on on to get ; then regress
Question 9
2.5 / 2.5 pts
Assume the true model is Denote the estimator for the estimator for as
, with . under OLS estimation, and denote under maximum likelihood estimation.
Which of the following statements is true?
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 10
0 / 2.5 pts
rrect Answer
u Answered
is BLUE and is biased and
is biased and is BLUE and
is inefficient is inefficient
is inefficient is inefficient
none of these answers are correct
Neither nor
is a consistent estimator of .
Question 11
0 / 2.5 pts
Which of the following statements is true about the two-stage least squares estimation?
The two-stage least squares estimator is inconsistent.
If the first-stage F-statistic is close to zero, then the instrument is not weak.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10
Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
u Answered
rrect Answer
Using a weak instrument would result in large finite sample bias in the two-stage least squares estimator.
rrect Answer u Answered
Assume the true model is , with . Which of the following statements is true about the maximum likelihood
estimator ?
is asymptotically normal.
is asymptotically normal. All of the statements are true.
Question 12
0 / 2.5 pts
and are asymptotically independent.
We want to include as many instruments as possible in the estimation to ensure that at least one of them is strong.
Question 13
0 / 2.5 pts
If you want to test whether and are uncorrelated in the model , which test could you use?
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
u Answered rrect Answer
Hausman test. F-test.
Joint t-test.
Question 14
2.5 / 2.5 pts
If you reject
using an test, you conclude that
or , or both
Question 15
2.5 / 2.5 pts
Because and are both unbiased, it is true that, regardless of the form of ,
none of these answers are correct.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
u Answered
rrect Answer
Suppose we have a linear regression model with heteroskedasticity:
George estimates both and
statements is true?
The relationship between depends on the determinant of
and . . Which of the following
The relationship between and depends on the trace of .
Question 16
0 / 2.5 pts
all of these answers are correct
Question 17
2.5 / 2.5 pts
The Gauss-Markov theorem will not hold if
the independent variables have perfect collinearity among them.
the error term has the same variance given any values of the explanatory variable.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
rrect Answer
will have a lower variance if we use model 1 instead of model 2 will be biased if we use model 1
Question 18
0 / 2.5 pts
of a regression
indicates the fraction of the variability in explained by the regression indicates whether the estimates would be unbiased
is highest for the true model
rrect Answer
u Answered
Suppose we observe , and for individuals. We wish to
investigate the relationship between and between two models, model 1 is given by and model 2 is given by
Suppose that we knew for a fact that
. We must choose
. Which of the following is
produces the most precise estimates
the regression model relies on the method of random sampling for collection of data.
the error term has an expected value of zero given any values of the independent variables.
Question 19
0 / 2.5 pts
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10
Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
u Answered
We are not sure whether would increase or decrease, because is non-monotonic in the number of regressors included in the
regression.
u Answered
rrect Answer
Assume you want to study how education affects income using a sample of 200 people. You regress income on education with an intercept. The of your regression is 0.6. What would happen to the
if you also included age as an additional regressor in your model? would decrease when age affects income negatively.
would increase.
would not change because the sample size has not changed.
u Answered
Question 20
0 / 2.5 pts
will be biased if we use model 2
will have a lower variance if we use model 2 instead of model 1
Question 21
0 / 2.5 pts
Suppose we have a linear regression model with heteroskedasticity:
, where and .
George estimates , the feasible generalized least square estimator. Which of the following statements is true about ?
is biased and inconsistent.
is unbiased and consistent.
o https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10
Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
rrect Answer
is biased and consistent.
is unbiased and inconsistent.
Assume the true model is
regression of on both and to get and unbiased?
. However, you run an OLS . When is
rrect Answer
u Answered
is always an unbiased estimator of . Only when .
Only when both and and are orthogonal” hold.
u Answered
Question 22
0 / 2.5 pts
Only when and
are orthogonal.
Question 23
0 / 2.5 pts
Assume the true relationship between and is
, , with for all , and
for . Denote the OLS estimator of as . A student wants to estimate using the new estimator
. Under the assumptions of the classical regression model, what are and respectively?
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
rrect Answer
When and squares estimator
Biased and Efficient Unbiased and efficient
Biased and Inefficient
, the ordinary least is:
rrect Answer u Answered
Question 24
0 / 2.5 pts
Unbiased and Inefficient
Question 25
2.5 / 2.5 pts
, where , where , where
. How do we estimate ?
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 26
2.5 / 2.5 pts
We have a sample of working individuals from a particular country and are interested in estimating the returns to education in that country. We estimate the model
, where is the hourly wage, is years of education, and
denotes years of labor market experience. In this country, however, females have restricted access to education. Unfortunately, we do not have information about the gender of the individuals in our sample. If gender is one of the unobserved determinants of wages (included in ), which of the following statements is true?
, the OLS estimator for , is biased and inconsistent if we don’t include the variable gender in the regression.
We can fix the problem of not observing gender by using instrumental variables estimation.
We have a problem of omitted variable bias because educ and gender are correlated, and gender is one of the determinants of wages.
All of these statements are true.
Question 27
2.5 / 2.5 pts
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
rrect Answer u Answered
correct? Including
Including Including
. Which of the following is
as a variable introduces perfect multi-colinearity.
will reduce the bias of .
will reduce the variance of .
Question 28
0 / 2.5 pts
George wants to estimate the relationship between and using a linear regression. George heard that including extra variables in the model can reduce variance so he proposes to use the model
none of these answers are correct
Question 29
2.5 / 2.5 pts
Under the assumptions of the classical regression model:
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 30
2.5 / 2.5 pts
the ordinary least squares estimator is the minimum variance linear unbiased estimator.
all of these answers are correct.
there may be biased estimators that have lower variance than the ordinary least squares estimator.
there may be non-linear estimators that have lower variance than the ordinary least squares estimator.
Question 31
0 / 2.5 pts
Suppose George uses a sample of 500 individuals to study how education and age affect income. He regresses income on education
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10
Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
and age with an intercept. Let his regression model be .
What is the dimension of 2 by 500.
3 by 500. 500 by 3.
in his model?
u Answered
rrect Answer
rrect Answer
u Answered
Suppose we observe
investigate the relationship between
between two models, model 1 is given by
and model 2 is given by
Suppose that we knew for a fact that is relevant ( and
Question 32
0 / 2.5 pts
are not orthogonal). Which of the following is true?
will be biased if we use model 1
using model 2 will introduce perfect multi-collinearity.
Using model 2 will prevent heteroskedasticity
for individuals. We wish to and . We must choose
will be biased if we use model 2
Question 33
2.5 / 2.5 pts
When and , the variance of the ordinary least squares estimator is:
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 34
0 / 2.5 pts
rrect Answer
u Answered
Assume the true model is . Under the assumptions of the classical regression model, which of the following statements is true about ?
is consistent and inefficient. is inconsistent and efficient. is inconsistent and inefficient.
is consistent and efficient.
Question 35
2.5 / 2.5 pts
Let represent sum of squared residuals from the restricted model of hypothesis testing, and represent sum of squared residuals of the unrestricted model. Let be the number of restrictions placed. Which of the following statements is true?
t-test is superior than F-test in testing a joint hypothesis.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 36
2.5 / 2.5 pts
Consider the equation, states that
has no effect on the expected value of has no effect on the expected value of
has no effect on the expected value of has no effect on the expected value of
. A null hypothesis,
The F statistic is always nonnegative as is never smaller than .
An F statistic that is close to zero leads to rejection of the null hypothesis.
Other things being equal, The F statistic increases with .
Question 37
2.5 / 2.5 pts
Suppose the true model is , where
. You plan to perform two-stage least squares estimation with a set of instrumental variables . Which one of the following is required for the two-stage least square estimation to work?
is uncorrelated with . .
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 38
0 / 2.5 pts
Assume the true model is run an OLS regression of
When is unbiased?
on only to get
are orthogonal.
. However, you
, the estimator of .
Only when both ” ” and ” and are orthogonal” hold.
u Answered
Only when Only when When either ”
rrect Answer
” or ” and are orthogonal” holds.
is uncorrelated with .
Question 39
2.5 / 2.5 pts
Assume the true model is . Denote the estimator for as under OLS estimation, and denote the estimator for as
under maximum likelihood estimation. Denote the estimator for
as under OLS estimation, and denote the estimator for as under maximum likelihood estimation. Which of the following
statements is true?
is an unbiased estimator of . All of the statements are true.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
2022/2/16 22:10 Midterm Exam: ECON 123B: ECONOMETRICS II (62200)
Question 40
0 / 2.5 pts
rrect Answer
u Answered
If and are given, every time you do , you will get the same answer. What is the idea, then, behind computing
show that OLS produces the most precise estimates
those quantities represent a statement about the behavior of
over repeated samples of , but don’t pertain to the distribution of given the current
given the current
Quiz Score: 50 out of 100 This quiz score has been manually adjusted by +2.5 points.
show that OLS is unbiased and inefficient
OLS estimation places a stronger assumption on than MLE does. None of the statements are true.
https://canvas.eee.uci.edu/courses/43789/quizzes/206572
程序代写 CS代考 加微信: powcoder QQ: 1823890830 Email: powcoder@163.com