28. Forecasts based on the random walk model are

a. Average forecasts

b. Naive Forecasts

c. Drift Forecasts

d. Moving Average Forecasts

Group of answer choices

29. If 95% of the spikes in the ACF plot of time series of length 100 fall between -0.2 and +0.2, then the time series is a ________________ time series.

a. ARIMA (1,0,1)

b. ARIMA (1,1,1)

c. ARIMA (0,0,0)

d. ARIMA (1,0,0)

30. Unit root tests are used for determining whether __________ is needed to produce stationarity in a time series.

31. A time series with a long term trend component can be made stationary by differencing.(True/False)?

32. The backshift operator B when applied to a time series y(t) produces the first difference y(t) - y(t-1). (True/False)?