I am trying to fit my data, attached, with the following model
CutOff <- 0
fit.full <- lme(fixed= zGrade ~ Rep + ISE +Yfrm7A +Ufrm7A +Female +White
+HSGPA +MATH +AP_TOTAL +Years +Course +
Course*Rep + Course*ISE +Course*Yfrm7A+Course*Ufrm7A
+Course*Female +Course*White +Course*HSGPA +Course*MATH +Course*AP_TOTA
L+Course*Years,
random= ~1|SID,
data = Master.complete[Master.complete$GRADE >= CutOff,])
I get the following error
Error in MEEM(object, conLin, control$niterEM) :
Singularity in backsolve at level 0, block 1
when I take out
+Course*Yfrm7A+Course*Ufrm7A
and just use
fit.full <- lme(fixed= zGrade ~ Rep + ISE +Yfrm7A +Ufrm7A +Female +White
+HSGPA +MATH +AP_TOTAL +Years +Course +
Course*Rep + Course*ISE
+Course*Female+Course*White+Course*HSGPA+Course*MATH+Course*AP_TOTAL+Course*Years,
random= ~1|SID,
data = Master.complete[Master.complete$GRADE >= CutOff,])
I don't get an error
I think this is because when Course == P7A Yfrm7A==Ufrm7A==0. I am not
sure how to work around this. any suggestions would be welcome.
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