Câu hỏi: The order of integration:

A. can never be zero

B. is the number of times that the series needs to be differenced for it to be stationary

C. is the value of \({\phi _1}\) in the quasi difference \(\Delta {Y_t} – {\phi _1}{Y_{t – 1}}\)

D. depends on the number of lags in the VAR specification

Câu 1: The advantage of using heteroskedasticity-robust standard errors is that:

A. that they are easier to compute than the homoskedasticity-only standard errors

B. they produce asymptotically valid inferences even if you do not know the form of the conditional variance function.

C. it makes the OLS estimator BLUE, even in the presence of heteroskedasticity

D. they do not unnecessarily complicate matters, since in real-world applications, the functional form of the conditional variance can easily be found

Câu 2: Giả sử với số quan sát n=20, ước lượng mô hình hồi qui:

A. Mô hình hồi qui không có tự tương quan

B. Không kết luận được

C. Mô hình hồi qui có Tự tương quan âm

D. Mô hình hồi qui có Tự tương quan dương

Câu 3: Asymptotic distribution theory is:

A. not practically relevant, because we never have an infinite number of observations

B. only of theoretical interest

C. of interest because it tells you what the distribution approximately looks like in small samples

D. the distribution of statistics when the sample size is very large

Câu 4: ARCH and GARCH models are estimated using the:

A. OLS estimation method

B. the method of maximum likelihood

C. DOLS estimation method

D. VAR specification

Câu 5: A VAR with five variables, 4 lags and constant terms for each equation will have a total of:

A. 21 coefficients

B. 100 coefficients

C. 105 coefficients

D. 84 coefficients

Câu 6: Under the five extended least squares assumptions, the homoskedasticity-only tdistribution in this chapter:

A. has a Student t distribution with n-2 degrees of freedom

B. has a normal distribution

C. has a Student t distribution with n degrees of freedom