R help - Jul 2018 - Formatting multi-way ANOVA output for spectra analysis

Dear Robert,

Although you don't say so, it sounds as if you may be using the Anova()
function in the car package, which is what the R Commander uses for ANOVA. If
so, in most cases, Anova() returns an object of class c("anova",
"data.frame"), which can be manipulated as a data frame. To see this,
try something like

str(Anova(your.model))

You should be able to extract, manipulate, and graph whatever components of the
object interest you.

I hope this helps,
 John

-----------------------------------------------------------------
John Fox
Professor Emeritus
McMaster University
Hamilton, Ontario, Canada
Web: https://socialsciences.mcmaster.ca/jfox/


> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Robert
D.
> Bowers M.A.
> Sent: Wednesday, July 25, 2018 1:12 PM
> To: r-help at r-project.org
> Subject: [R] Formatting multi-way ANOVA output for spectra analysis
> 
> I've studied R a little bit, although I haven't used it in some
time (except via
> RCommander).? I'm working on my dissertation project and have
> spectrometer data that I need to evaluate.? I need to find a way to
simplify the
> output from multi-way ANOVA so I can reduce the areas of the spectrum to
> only those where there are significant differences between sites.? (A
> preliminary study on a too-small sample size indicates that certain areas
of
> the spectrum can distinguish between sites.? This project is the next
step.)
> 
> The dataset is comprised of analyses done on samples from five separate
> locations, with 50 samples taken from each site.? The output of the
> spectrometer per sample is values for 2048 individual wavelengths, in a
> spreadsheet with the wavelength as the first column.? Since I'm doing
the
> analysis wavelength-by-wavelength, I've transposed the data and broke
the
> data for the project down into smaller spreadsheets (so that R can perform
> ANOVA on each wavelength).
> 
> The problem is, I can do ANOVA now on each wavelength, but I don't need
a
> full output table for each... I just need to know if there is significant
variation
> between any of the sites at that wavelength, based on 95% confidence level
> (or better).? If I could get some sort of simple chart (or a single line in
a
> spreadsheet), that would help to narrow down the areas of the spectrum that
I
> need to focus on to evaluate the results of the tests.
> 
> I've been reading information about ANOVA, but have found very little
that is
> clear about formatting the output - and I don't need to rehash all of
the
> math.? I just need to find out how to hack down the output to just the part
I
> need (if possible).? Once that's done, I can decide what wavelengths
are
> valuable for future tests and simplify the process.
> 
> Thanks for any help given!
> 
> Bob
> 
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