Predefined Contrasts
Click the Other button in the Contrasts for Dependent Variables dialog to display the Predefined Contrasts dialog.
Contrast
Select one of the following predefined contrasts under Contrast:
Deviation
This type of contrast compares the deviations from the grand mean of the dependent variable, for example for a factor with 3 levels, the following matrix of contrasts would be created:
| 2 | -1 | -1 |
| -1 | 2 | -1 |
Difference
This type of contrast compares the levels of a variable with the mean of the preceding levels of that variable, for example for a factor with 3 levels, the following matrix of contrasts would be created:
| -1 | 1 | 0 |
| -1 | -1 | 2 |
Helmert
This is the Helmert contrast matrix, for example for a factor with 3 levels, the following matrix of contrasts would be created:
| 2 | -1 | -1 |
| 0 | 1 | -1 |
Simple
This type of contrast compares a preceding level of a variable with the last level of that variable, for example for a factor with 3 levels, the following matrix of contrasts would be created:
| 1 | 0 | -1 |
| 0 | 1 | -1 |
Repeated
This type of contrast compares adjacent levels of a variable, for example for a factor with 3 levels, the following matrix of contrasts would be created:
| 1 | -1 | 0 |
| 0 | 1 | -1 |
OK
Click the OK button to close the dialog and return to the
Contrasts for Dependent Variables dialog. The Contrast that you have selected will be entered into the contrast specification columns in this dialog.
Cancel
Click the Cancel button to close the dialog and return to the
Contrasts for Dependent Variables dialog, disregarding any changed that you have made.
See also GLM - Index.