[R] Within Subject ANOVA question

[tsunhin wong]

As another follow-up related to aov, I want to extract values
(Residual interaction mean square & interaction DF) from the results:
asummary<-summary(aov.recall)
The results are in a list() format with 3 lists, and contents within
each list are without "names".

I am not able to do something like in other statistics such as in t.test:
>as.numeric(t.test(serie1,serie2,na.rm=TRUE)$statistic)

What method should I use to extract, or is it simpler to write compute
the figures that I need directly in this case?
Thanks a lot!

- John

On Mon, Jun 1, 2009 at 7:08 PM, Mike Lawrence <Mike.Lawrence at dal.ca> wrote:
> On Mon, Jun 1, 2009 at 7:50 PM, tsunhin wong <thjwong at gmail.com> wrote:
>> But I have some follow-up questions:
>> 1. In aov, why IVs (subject & condition) cannot be in number format?
>
> Put simply, because that's the only way to obtain the values you
> observe in the paper you're reading. :Op  Factorizing tells the ANOVA
> that the labels associated with each level of the factor aren't really
> meaningful. This is particularly evident in the case of Subject
> numbers, which (typically) have no numeric interpretation (Ss #6 is
> not 2 times Ss #3). The original authors' choice to treat condition as
> a factor was a less clear choice given that it clearly refers to a
> measurable ratio quantity (seconds). I presume the paper to which
> you're referring is the Masson & Loftus 1994 paper (be sure to read
> their 2003 follow-up and 2004 correction). In that case the authors
> come from a field where it's commonplace to treat even ratio
> independent variables as factored.
>
>> 2. Why I need to use factor() on IVs (subject & condition) but I
>> cannot use factor() on DV (recall)?
>
> As noted above, factoring prohibits R from interpreting the labels of
> a value as numerically meaningful, something you surely do not want to
> do with your DV in this example.
>
>
> --
> Mike Lawrence
> Graduate Student
> Department of Psychology
> Dalhousie University
>
> Looking to arrange a meeting? Check my public calendar:
> http://tr.im/mikes_public_calendar
>
> ~ Certainty is folly... I think. ~
>