The worksheet for
the example is below. After the titles in column A, columns
B and C hold the unit values of the investments. If the investments
were stocks, the values would be the stock price per share.
Columns D holds the moving average forecast of the unit value
of Investment 1 for t periods beyond the data period.
The number of periods specified in cell C3 is 2 for the example
however this number can be changed. All components of the portfolio
have the same forecast time. Formulas in E3 and H3 link these
values to the contents of C3. Column F holds the forecast error
for the first investment. Columns H and I hold the forecast
and forecast error for Investment 2.
Columns J and K hold the number of units owned of the two
investments. These numbers are under the control of the investor.
Column L holds the total portfolio value for each period.
It is the sum over the investments of the product of the unit
values and the numbers of units owned. Column M holds the forecasted
value of the portfolio. It is the sum over the investments
of the product of the forecasted value and the number of units
owned. The last column is the error in the forecasts.
The last few rows have no data indicating that the last observation
is in period 7. As time passes data will be added and forecasts
revised. The change option can be used to add more rows or
move up time.