'signedF'

This argument is optional. It is a small trick for advanced users.
it is a Boolean used only in the case where each factor Ai has exactly two levels, with means mi1 and mi2 for the levels 1 and 2 of the ith factor.
If mi1<mi2, the F value for the effect of Ai will be multiplied by -1.

Note: This argument is a boolean and is single (i.e. is not a named argument with a name and a value)

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