[R] linear mixed model using lmer

[Jixiang Wu]

There is no difference when running anova or t-test. So you shouldn't
expect positive variance between batches.

On Fri, Mar 4, 2022 at 7:06 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.
>
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>
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