t; To: tedtoal
> Cc: r-help@r-project.org
> Sent: Wednesday, July 25, 2012 6:21 AM
> Subject: Re: [R] Between-group variance from ANOVA
>
> There is nothing about R in your question, hence it is not appropriate
> for this list. Please consult with a local statistician, or post on a
&
sta Zahn
To: tedtoal
Cc: r-help@r-project.org
Sent: Wednesday, July 25, 2012 6:21 AM
Subject: Re: [R] Between-group variance from ANOVA
There is nothing about R in your question, hence it is not appropriate
for this list. Please consult with a local statistician, or post on a
stats help list
> > I'm trying also to understand how to get the between-group variance
> > out of a one-way ANOVA, but I'm beginning to think that in a sense,
> > the variance does not exist. Emma said:
> >
> > *The model is response(i,j)= group(i)+ error(i,j)*
> >
> > Yes, if by group(i) you mean intercept
There is nothing about R in your question, hence it is not appropriate
for this list. Please consult with a local statistician, or post on a
stats help list such as http://stats.stackexchange.com/
On Tue, Jul 24, 2012 at 8:55 PM, tedtoal wrote:
> I'm trying also to understand how to get the betwe
I'm trying also to understand how to get the between-group variance out of a
one-way ANOVA, but I'm beginning to think that in a sense, the variance does
not exist. Emma said:
*The model is response(i,j)= group(i)+ error(i,j)*
Yes, if by group(i) you mean intercept + coefficient[i].
*we assume
I have done this in R and this is the following ANOVA table I get:
> summary(aov(response ~ group, data=TDat))
Df Sum Sq Mean Sq F valuePr(>F)
group 1 11203.5 11203.5 2505.0 < 2.2e-16 ***
Residuals 198 885.5 4.5
The model is response(i,j)= group(i)+ error(i,j),
can anyone advise me please?
emj83 wrote:
>
> I have done some ANOVA tables for some data that I have, from this I can
> read the within-group variance. can anyone tell me how i may find out the
> between-group variance?
>
> Thanks Emma
>
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Hi Emma,
...
I forgot to add the tabular ouput, which doesn't help either:
T.sum <- summary(aov(response ~ group, data=TDat))
print(T.sum)
Df Sum Sq Mean Sq F valuePr(>F)
group 1 11225.2 11225.23084 < 2.2e-16 ***
Residuals 198 720.7 3.6
Hi Emma,
>> ...from this I can read the within-group variance. can anyone tell me how
>> i may find
>> out the between-group variance?
But it's in the table, above the "within-group" variance. Remember that F is
the ratio of these two quantities, i.e. the mean of the group variances
divided by
Hi Emma,
>>
R gives you the tools to work this out.
## Example
set.seed(7)
TDat <- data.frame(response = c(rnorm(100, 5, 2), rnorm(100, 20, 2)))
TDat$group <- gl(2, 100, labels=c("A","B"))
with(TDat, boxplot(split(response, group)))
summary(aov(response ~ group, data=TDat))
Regards, Mark.
e
I have done some ANOVA tables for some data that I have, from this I can read
the within-group variance. can anyone tell me how i may find out the
between-group variance?
Thanks Emma
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View this message in context:
http://www.nabble.com/Between-group-variance-from-ANOVA-tp24954045p24954045.htm
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