Time Series Analysis ARIMA Models 2

Question 1

Which information criterion is commonly used for ARIMA model selection?

Accepted Answer

AIC (Akaike Information Criterion)

Answer

R-squared

Answer

Mean Absolute Error

Answer

Durbin-Watson statistic

Question 2

What does a significant Ljung-Box test on ARIMA residuals indicate?

Accepted Answer

Residual autocorrelation remains — model is inadequate

Answer

The model fits perfectly

Answer

Stationarity is confirmed

Answer

Seasonality is absent

Question 3

For a SARIMA model ARIMA(1,1,1)(1,1,1)[12], what does the [12] represent?

Accepted Answer

Seasonal period of 12 months

Answer

12 AR lags

Answer

12 MA lags

Answer

12 differencing steps

Question 4

What condition must be satisfied for an AR(p) model to be stationary?

Accepted Answer

All roots of the characteristic polynomial must lie outside the unit circle

Answer

All roots must lie inside the unit circle

Answer

The mean must equal zero

Answer

Variance must be zero

Question 5

Which function in Python's statsmodels library is commonly used to fit ARIMA models?

Accepted Answer

ARIMA()

Answer

arima_fit()

Answer

fit_arima()

Answer

time_series_arima()

Question 6

What is the Box-Jenkins methodology primarily used for?

Accepted Answer

Systematic identification, estimation, and diagnostic checking of ARIMA models

Answer

Only visualizing time series data

Answer

Computing seasonal indices

Answer

Calculating moving averages