You can change the bounds or limits of each distribution, except the custom distribution, by dragging the truncation grabbers or by entering different numeric endpoints for the truncation grabbers. This "truncates" the distribution. You can also exclude a middle area of a distribution by crossing over the truncation grabbers to "white out" the portion to exclude.
To display the truncation grabbers, open an assumption in the Define Assumption dialog and click the More button beside the assumption name field. |
For example, suppose you want to describe the selling price of a house up for auction after foreclosure. The bank that holds the mortgage will not sell for less than $80,000. They expect the bids to be normally distributed around $100,000 with a standard deviation of $15,000. In Crystal Bally, ou would specify the mean as 100,000 and the standard deviation as 15,000 and then move the first (left) grabber to set the limit of 80,000. The grabber "whites out" the portion to exclude, as shown in Figure 130, Truncated distribution example.
