
Dear:

I am working on gamma mixed model. I have used...... lmer().... to model the data set. Here is the short part of the data.....

      obs treat*  id time response timesq responsebin
1       1     0   2    0      4.0      0           0
2       2     0   2    1      6.0      1           0
3       3     0   2    2      7.0      4           0
4       4     0   2    3      9.0      9           0
5       5     0   2    6     13.0     36           0
8       8     0   3    1      1.0      1           0
9       9     0   3    2      2.0      4           0
10     10     0   3    3      3.0      9           0
11     11     0   3    6      9.0     36           0
12     12     0   3    9      4.0     81           0
13     13     0   3   12      2.0    144           0


*treatment has two groups......... 0 and 1

I used the model ....

m1.3.cg2<-lmer(response~time+timesq+factor(treat)+(1|time)+(1|id)+(time|id),data=dcg,
family=Gamma(link = "identity"))

And it shows the warning message like........

Warning message:
In mer_finalize(ans) : singular convergence (7)

Moreover, the result it shows is quite confusing due to large estimated value of fixed effects..................

My concern is whether I should keep the model with such warning message or not?

And what this warning message indicates?

Any comments or suggestion would be highly appreciable.

Thank you.

Rajibul Mian, Grad student, UNB, Canada

 
 		 	   		  
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