Menu: View→Analysis Properties→Bias→Covariances to be analyzed→Unbiased
Fits the sample covariance matrix that is an unbiased estimate (rather than the maximum likelihood estimate).
For more information, see the FitUnbiasedMoments method of the AmosEngine class.
Programming
In Amos Graphics programs, you can select this option by using the following statement (Visual Basic):
pd.GetRadioButton("AnalysisPropertiesForm", "OptionUseBias_Unbiased").Checked = True