I'm trying to implement a regression model with both fixed and random effects. The package I use is the
I want to find the relationship between the continuous variables
X2, using the categorical variable
F1 as a fixed effect.
When I try to implement the model
model <- lmer(X1 ~ F1 + (1|X2)) I get the following error:
Number of levels of a grouping factor for the random effects must be less than the number of observations
My understanding for the error is that the
X2 varies less than the
X1 (which has some similar values). Why is this a problem?