ARIMA models decompose time series data into three components: an autoregressive (AR) process which accounts for the influence of past values, an integrated (I) process which filters non-stationary data, and a moving average (MA) process which accounts for residual autocorrelation. The document provides instructions on running an ARIMA model in three steps: selecting historical time series data on US money supply, inputting the ARIMA model parameters (p,d,q), and generating a forecast.
2. ARIMA modeling:
In briefly, ARIMA econometric modeling takes into account
historical data and decomposes it into an Autoregressive
(AR) process, where there is a memory of past events (e.g.,
the interest rate this month is related to the interest rate
last month, and so forth, with a decreasing memory lag).
ARIMA models has three model parameters, one for the
AR(p) process, one for the I(d) process, and one for the
MA(q) process, all combined and interacting among each
other and recomposed into the ARIMA (p,d,q) model.
3. Data
The Data worksheet contains some
historical time-series data on money
supply in the United States, denoted
M1, M2, and M3. M1 is the most
liquid form of money (cash, coins,
savings accounts, and so forth);
while M2 and M3 are less liquid
forms of money (bearer bonds,
certificates of deposit, and so forth).
4. Running a ARIMA
1. Go to the Data worksheet and
select Risk Simulator l
Forecasting l ARIMA.
2. Click on the LINK icon beside the
Time Series Variable input box,
and link in C7:C442.
3. Enter in the relevant P, D, Q
inputs, forecast periods,
maximum iterations, and so
forth.