[R] Performing gage R&R study in R w/more than 2 factors

[Bert Gunter]

I believe that you need to consult a local statistician, as there are
likely way too many statistical issues here that you do not fully
understand. Alternatively, try posting to a statistical list like
stats.stackexchange.com, as I think most of your issues are primarily
statistical, not R related.

Cheers,
Bert

On Mon, Nov 19, 2012 at 11:12 AM, Matt Jacob <matt at jacobmail.org> wrote:
> Hi everyone,
>
> I'm fairly new to R, and I don't have a background in statistics, so
> please bear with me. ;-)
>
> I'm dealing with 2^k factorial designs, and I was just wondering if
> there's any way to analyze more than two factors of a gage R&R study in
> R. For example, Minitab has an "expanded gage R&R" function that lets
> you include up to eight additional factors besides the usual two that
> are present in gage studies (parts and operators). If I wanted to
> include n additional random factors, is there a package or built-in
> functionality that will allow me to do that?
>
> I've been experimenting with the SixSigma package, and that has a ss.rr
> method which works great---as long as your experiment only contains two
> factors. I've also been using lmer from lme4 to fit a linear model of my
> experiment, but the standard deviations generated by lmer don't match
> what I'm seeing in Minitab. Since all my factors are random, the formula
> I'm using looks like this:
>
> vals ~ 1 + (1|f1) + (1|f2) + (1|f3) + (1|f1:f2) + (1|f1:f3) + (1|f2:f3)
>
> What am I doing wrong, and how can I fix it?
>
> Thanks,
>
> Matt
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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