If some observations have erratic data because of special causes that you have already corrected, you can omit these observations from the calculations to avoid incorrect parameter estimates.
In Omit the following observations when estimating parameters (optional), enter the observations. Use a colon to indicate a range of observations. Leave a space between each observation or range of observations. For example, to specify observations 4, 7, 11, 12, 13, and 14, enter 4 7 11:14.