I'm struggling to understand the meaning of fixed effects coefficients calculated by fitlme. Suppose I have a fixed factor with 3 levels, so level 1 is the reference. The fixed effects coefficients table provides estimates for the levels 2 and 3. If these estimates are significant (i.e., the interval between the upper and lower CIs does not include 0), does this mean that these levels are significantly different from level 1? If this is the case, how can I determine if levels 2 and 3 are significantly different from each other? If my interpretation is wrong, what does the fixed effects coefficients statistics means?