[R] help with statistics in R - how to measure the effect of users in groups

[Petr PIKAL]

> 
> Hi Petr,
> 
> It's not an equation. It's my mistake; the * are meant to be field
> separators for the example data. I should have just use blank spaces as
> follows:
> 
> users   Group1   Group2   Group3
> u1        10           5            N/A
> u2         6          N/A          4
> u3         5           2            3
> 
> 
> Regards
> Gawesh

OK. You shall transform your data to long format to use lm

test <- read.table("clipboard", header=T, na.strings="N/A")
test.m<-melt(test)
Using users as id variables
fit<-lm(value~variable, data=test.m)
summary(fit)

Call:
lm(formula = value ~ variable, data = test.m)

Residuals:
   1    2    3    4    6    8    9 
 3.0 -1.0 -2.0  1.5 -1.5  0.5 -0.5 

Coefficients:
               Estimate Std. Error t value Pr(>|t|) 
(Intercept)       7.000      1.258   5.563  0.00511 **
variableGroup2   -3.500      1.990  -1.759  0.15336 
variableGroup3   -3.500      1.990  -1.759  0.15336 
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Residual standard error: 2.179 on 4 degrees of freedom
  (2 observations deleted due to missingness)
Multiple R-squared: 0.525,      Adjusted R-squared: 0.2875 
F-statistic: 2.211 on 2 and 4 DF,  p-value: 0.2256 

No difference among groups, but I am not sure if this is the correct way 
to evaluate.

library(ggplot2)
p<-ggplot(test.m, aes(x=variable, y=value, colour=users))
p+geom_point()

There is some sign that user3 has lowest value in each group. However for 
including users to fit there is not enough data.

Regards
Petr 


>
> 
> On Mon, Oct 10, 2011 at 9:32 AM, Petr PIKAL <petr.pikal at precheza.cz> 
wrote:
> 
> > Hi
> >
> > I do not understand much about your equations. I think you shall look 
to
> > Practical Regression and Anova Using R from J.Faraway.
> >
> > Having data frame DF with columns - users, groups, results you could 
do
> >
> > fit <- lm(results~groups, data = DF)
> >
> > Regards
> > Petr
> >
> >
> >
> >
> > >
> > > Hi,
> > >
> > > I'm a newbie to R. My knowledge of statistics is mostly self-taught. 
My
> > > problem is how to measure the effect of users in groups. I can 
calculate
> > a
> > > particular attribute for a user in a group. But my hypothesis is 
that
> > the
> > > user's attribute is not independent of each other and that the 
user's
> > > attribute depends on the group ie that user's behaviour change based 
on
> > the
> > > group.
> > >
> > > Let me give an example:
> > >
> > > users*Group 1*Group 2*Group 3
> > > u1*10*5*n/a
> > > u2*6*n/a*4
> > > u3*5*2*3
> > >
> > > For example, I want to be able to prove that u1 behaviour is 
different
> > in
> > > group 1 than other groups and the particular thing about Group 1 is 
that
> > > users in Group 1 tend to have a higher value of the attribute under
> > > measurement.
> > >
> > >
> > > Hence, can use R to test my hypothesis. I'm willing to learn; so if 
this
> > is
> > > very simple, just point me in the direction of any online resources
> > about
> > > it. At the moment, I don't even how to define these class of 
problems?
> > That
> > > will be a start.
> > >
> > > Regards
> > > Gawesh
> > >
> > >    [[alternative HTML version deleted]]
> > >
> > > ______________________________________________
> > > R-help at r-project.org mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > > and provide commented, minimal, self-contained, reproducible code.
> >
> >
> 
>    [[alternative HTML version deleted]]
> 
> ______________________________________________
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http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.