Filter
Top Products
48
Example 2
You can see that the parameters that were specified to be equal do have equal
estimates. The standard errors here are generally smaller than the standard errors
obtained in Example 1. Also, because of the constraints on the parameters, there are
now positive degrees of freedom.
E Now click Notes for Model in the upper left pane of the Amos Output window.
While there are still 10 sample variances and covariances, the number of parameters to
be estimated is only seven. Here is how the number seven is arrived at: The variances
of recall1 and recall2, labeled v_recall, are constrained to be equal, and thus count as
a single parameter. The variances of place1 and place2 (labeled v_place) count as
another single parameter. A third parameter corresponds to the equal covariances
recall1 <> place1 and recall2 <> place2 (labeled cov_rp). These three parameters,
plus the four unlabeled, unrestricted covariances, add up to seven parameters that have
to be estimated.
The degrees of freedom ( ) may also be thought of as the number of
constraints placed on the original 10 variances and covariances.
Optional Output
The output we just discussed is all generated by default. You can also request additional
output:
E From the menus, choose View > Analysis Properties.
E Click the Output tab.
E Ensure that the following check boxes are selected: Minimization history, Standardized
estimates
, Sample moments, Implied moments, and Residual moments.
10 7 3=–