[R] linear mixed model using lmer

[Bert Gunter]

Do you really think a variance from a sample size of 2 makes any sense?

Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Fri, Mar 4, 2022 at 5:06 PM array chip via R-help
<r-help using r-project.org> wrote:
>
>  Thanks Jeff for reminding me that the attachment is removed. I put it in my google drive if anyone wants to test the data (https://drive.google.com/file/d/1lgVZVLHeecp9a_sFxEPeg6353O-qXZhM/view?usp=sharing)
> I'll try the mixed model mailing list as well.
> John
>     On Friday, March 4, 2022, 04:56:20 PM PST, Jeff Newmiller <jdnewmil using dcn.davis.ca.us> wrote:
>
>  a) There is a mailing list for that: https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models
>
> b) Read the Posting Guide, as most attachment types are removed to avoid propagating worms/viruses. (None seen upon receipt of this email.)
>
> On March 4, 2022 4:41:57 PM PST, array chip via R-help <r-help using r-project.org> wrote:
> >Dear all, I have this simple dataset to measure the yeild of a crop collected in 2 batches (attached). when I ran a simple inear mixed model using lmer to estimate within-batch and between-batch variability, the between-batch variability is 0. The run showed that data is singular. Does anyone know why the data is singular and what's the reason for 0 variability? is it because the dataset only has 2 batches?
> >> daty<-read.table("datx.txt",sep='\t',header=T,row.names=NULL)
> >> library(lme4)> lmer(yield~1+(1|batch),daty)
> >boundary (singular) fit: see ?isSingular
> >Linear mixed model fit by REML ['lmerMod']
> >Formula: yield ~ 1 + (1 | batch)
> >   Data: daty
> >REML criterion at convergence: 115.6358
> >Random effects:
> > Groups   Name        Std.Dev.
> > batch    (Intercept) 0.000
> > Residual             2.789
> >Number of obs: 24, groups:  batch, 2
> >Fixed Effects:
> >(Intercept)
> >      5.788
> >
> >Thanks!
> >John
> --
> Sent from my phone. Please excuse my brevity.
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.