which is correct way to specify the random effects? when using mixed effect, which type of model is appropriate? why use mixed waves instead of the country and wave what is the random effect lmer model can a mixed effect model be used to find the country and the wave what is nested random effect in lmer? what is random effects in lmer why is mixed effect model appropriate when are random effects determined for the country how often to use a mixed effects model how to specify the mixed effects in lmer which is a common way to specify the random effects of a given wave what is the random effects of one wave in lmer why use mixed models which model is used for the random effects in the country wave? when are mixed random effects models appropriate what is the ____ of a random effects wave which condition should be applied when the random effects are nested in the lmer model? why do we need a mixed effect why lmer mixed effects