- [Instructor] I'm starting in the exercise file 02 01 Begin…in the Add Forecast Error worksheet.…Often I find it useful to keep two copies of the forecasts…on the worksheet where I do the analysis.…We've already put forecasts…for the seasonal smoothing baseline in column K.…Those forecasts start in cell K7.…The forecast 7950 is actually the forecast…for the next period, just as it says in cell K1.…
Most of the data in row seven pertains to time period six.…And in the normal course of events…you would wait for all the data for time period six…before you made your forecast for time period seven.…But you would normally want to know your forecast…for time period seven before the actual data…for that period became available.…Often you're just at the tail end of period six…when you make your forecast for period seven.…So to help keep myself straight…I do my calculations for the forecast…of period seven in row seven.…
Then I link a cell in row eight…back to the forecast made in row seven.…That's important, because several of the calculations…
- Identify what distinguishes seasonality from a trend or a cycle.
- Explore how to use absolute and relative references in defined names, and recall that absolute reference always remain static while relative references change depending on precedent.
- Identify seasonality in a baseline by examining autocorrelation functions in a correlogram.
- Explore how to initialize seasonal effects in a baseline.
- Forecast the current level of the baseline and the current seasonal effect from prior observations, forecasts, and smoothing constants.
- Quantify a measure of the aggregate error in a forecast, and minimize it using Solver.
- Establish a baseline in a data object and forecast from that baseline in R.
- Compare Excel and R results.