Let's say I have 4 variables on the within person level - xa, ya, xb, yb. xa and ya have each 100 trials, xb and yb have 200, and there are 150 subjects. I want to build the following multilevel model in Mplus:
CLUSTER = subject; WITHIN = ya, yb; ANALYSIS: TYPE = TWOLEVEL RANDOM; MODEL: %WITHIN% sa | ya ON xa; sb | yb ON xb; %BETWEEN% G BY sa sb;
So basically, I extract the random slopes from the within person level regression a and b and use them to model another factor G on the between person level. The issue is that Mplus calculates the whole model only on 100 rows where all 4 variables have non-missing values, although regressions ya on xa, and yb on xb are done independently of each other. I hoped that Mplus will calculate the a regression on 100 trials and extract 150 random slopes for all people, and that it will calculate the b regression on 100 trials, and again extract 150 random slopes for all people. Then, on the between person level we would be able to model the latent variable G with two variables that each have 150 values....
However, Mplus always calculates the random effects only on 100 trials. How can I correct this?
This is the warning I get
*** WARNING Data set contains cases with missing on x-variables. These cases were not included in the analysis. Number of cases with missing on x-variables: 100 1 WARNING(S) FOUND IN THE INPUT INSTRUCTIONS SUMMARY OF ANALYSIS Number of groups 1 Number of observations 100