I have a categorical fixed effect with 3 levels that I'm trying to enter into an LME.
a = lmer(Reaction ~ ContinuousEffect * CategoricalEffect + (1|Subject) + (1|StrengthOfStimulus))
StrengthOfStimulus
is a numerical variable that's being used as a random effect, along with Subject
.
Now, for some reason, when I run this model I only get information on two levels of the CategoricalEffect, when there are really three levels:
Fixed effects:
Estimate Std. Error t value
(Intercept) 6.853550 0.035681 192.08
ContinuousEf -0.005463 0.002046 -2.67
TypeB -0.213765 0.010707 -19.97
TypeC -0.198775 0.010595 -18.76
Where A, B, and C are the levels of the CategoricalEffect
.
What happened to level A?