Help on using the menu for changing contrasts
This menu allows to change contrasts for one or more factors.
Contrary to R-Commanders native contrast changing function,
it simultaneously treats the matrix desnum for the design object,
so that the integrity of the class design
object is maintained.
Furthermore, it uses the contrast functions from base R rather than
those from package car.
One or more factors can be selected from the list on the left and moved to the list on the right. On OK, all factors from the RHS list are assigned the chosen contrast.
Note that the default contrast setting is “Treatment (dummy) coding”, regardless of the current factor coding.
Ulrike Groemping
See also change.contr for the function
that does the work