The forecast chart shows not only the range of results for each forecast, but also the probability, or certainty, of achieving results within a range. Certainty is the percent chance that a forecast value will fall within a specified range.
By default, the certainty range is from negative infinity to positive infinity. The certainty for this range is always 100 percent. However, you might want to estimate the chance of a forecast result falling in a specific range, say from zero to infinity (which you might want to calculate to ensure that you make a profit).
For example, consider the forecast chart in Figure 5, Certainty of a $2 Million Net Profit. If your objective is to make a minimum return of $2,000,000, you might choose a range of $2,000,000 to +Infinity. In this case, the certainty is almost 75 percent.