By default, after you add specification limits and a target to a forecast, markers for these values are displayed on the forecast chart.
The certainty range on the forecast chart changes to match the LSL and USL values. The certainty indicates the probability of falling within those specification limits. To show the certainty of different values, type them into the Minimum and Maximum text boxes or click the certainty grabbers and drag them to a new position.
To add specification limit and target marker lines manually or to remove them:
Notice that you can display the mean and other marker lines in addition to the specification limit and target markers.