Hi,
I have done tests of normality and heteroskedasticity for the level 1 data using qq plots on MLwiN and they are coming up with two separate lines of residuals (next to each other with a break in the middle for normality, and on top of each other for heteroskedasticity). Has anyone had this happen before and if so is this normal? I wondered if it is showing the residuals for each of the two outcomes?
Any ideas would be much appreciated.
Thanks,
Kat
Binary outcome qq plots for assumptions
Re: Binary outcome qq plots for assumptions
This quite usual and to be expected due to the binary nature of the response  see for single level models
http://www.ats.ucla.edu/stat/stata/webb ... talog3.htm
In multilevel models, the qq plots are more useful for the Normality assumption of the higherlevel residuals
http://www.ats.ucla.edu/stat/stata/webb ... talog3.htm
In multilevel models, the qq plots are more useful for the Normality assumption of the higherlevel residuals

 Posts: 4
 Joined: Mon Mar 17, 2014 9:38 am
Re: Binary outcome qq plots for assumptions
That's really helpful. Thanks!

 Posts: 1
 Joined: Tue Sep 21, 2021 10:15 pm
Re: Binary outcome qq plots for assumptions
This is fairly common and to be expected given the binary character of the response  see for singlelevel models.
The qq plots are more useful in multilevel models for the Normality assumption of the higherlevel residuals.
That is really useful. Thanks!
The qq plots are more useful in multilevel models for the Normality assumption of the higherlevel residuals.
That is really useful. Thanks!