[R] Learning ANOVA
maechler at stat.math.ethz.ch
Tue Aug 17 08:39:04 CEST 2010
>>>>> Liaw, Andy <andy_liaw at merck.com>
>>>>> on Mon, 16 Aug 2010 08:22:33 -0400 writes:
> From: Stephen Liu
>> Hi JesperHybel,
>> Thanks for your advice.
>> >If you're trying to follow the youtube video you have a
>> typing mistake here:
>> >InsectSprays.aov <-(test01$count ~ test01$spray)
>> >I think this should be:
>> >InsectSprays.aov <-aov(test01$count ~ test01$spray)
>> Your advice works for me. Sorry I missed "aov" before(test01$count ~
> I just want to offer another point: If you see any
> tutorial/document/book advising you to use model formula as above; e.g.,
> anything like
> df$var1 ~ df$var2 + df$var3
> Just run away from it as fast as you can, and try to wipe it from your
> memory. That's about the worst way to use a model formula, and very
> likely to give you what may seem to be strange problems down the road.
> Well-written model fitting functions should be called like this:
> modelfn(var1 ~ var2 + var3, data=df, ...)
YES, indeed, do run away from such bad R teaching...
and maybe really consider reading the tutorials and manuals we
list on http://www.r-project.org/ or buy a good (not thick!)
book introducing R rather than watching some youtube videos...
Do people now go to Youtube instead of to School and University?
O tempora, o mores!
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