Fun with Time Series Analysis

Which one of the following statement BEST describes the time series plot for the period shown?

• It shows no trend and no change in variability

• It shows increasing linear trend with constant variability

• It shows increasing trend with decreasing variability

• It shows increasing linear trend with increasing variability

The time series plot has

• no trend

• seasonality only

• an increasing trend with seasonality

• an increasing trend only

Select ALL statements that are true about this time series plot.

• Negative trend

• Positive trend

• Seasonality

• Random walk

Based on the ACF plot, select the appropriate ARIMA models that could be tested during the estimation phrase.

• ARIMA(1,1,0)

• ARIMA(0,1,1)

• ARIMA(1,1,1)

• All of the above

After selecting an ARIMA model, you examine the ACF/PACF residuals. Based on this plot, what can you conclude?

• The ARIMA model is a good fit.

• The time series is significant

• The ARIMA model is NOT a good fit.

• The intervention was not significant.

After graphing your time series data and seeing this plot, what should be your next step?

• Examine residuals

• Make it stationary through differencing

• Estimate models from ACF/PACF plots

• Check parameter estimates

Which of the following research scenarios would time-series analysis be best for?

• Measuring differences in two groups' cumulative GPA at the 1st, 2nd, 3rd, and 4th year of university.

• Finding the best predictive model based on a set of given variables.

• Measuring the effect of an intervention on daily behavior infractions over an entire school year.

• Measuring the time it takes for something to happen based on a given number of variables.