Hello,

I have run a linear mixed model to test the within-subject difference in activity behaviours (eg sleep, sedentary time etc) between 2 different timepoints (school vs. holidays). The trouble is, there is unequal variance in the activity behaviours. I'm wondering how I should deal with this.

An example of the syntax I am using is below. i.time_new refers to summer vs. school timepoints, and the participants are nested in schools and in waves.

mixed activity behaviour i.time_new || wave: || schoolid: || id:

Thanks for your help.