[R] Is it ok to apply the z.test this way?
Atte Tenkanen
attenka at utu.fi
Fri Apr 16 21:39:08 CEST 2010
Hi,
In fact, my original intention is to show that the measurings of the musical data are not random. Here I have a measurement from a composition.
http://www.ag.fimug.fi/~Atte/Comp.pdf
and here one random composition which I have used, among many others, in order to produce that 'Distribution'.
http://www.ag.fimug.fi/~Atte/RandomComp.pdf
All the values are averaged over the bars. That's why the curves are so smooth.
Is there any way to find such boundaries?
Atte Tenkanen
University of Turku, Finland
Department of Musicology
+35823335278
http://users.utu.fi/attenka/
----- Original Message -----
From: Christos Argyropoulos <argchris at hotmail.com>
Date: Friday, April 16, 2010 10:24 pm
Subject: RE: [R] Is it ok to apply the z.test this way?
To: attenka at utu.fi, r-help at r-project.org
> So ..
>
> are you trying to figure out whether your data hasa substantial number
> of outliers that call into question the adequacy of the normal distro
> fro your data?
>
>
>
> If this is the case, note that you cannot individually check the
> values (as you are doing) without taking into account of the
> "Bonferoni" fallacy i.e. small p-values will be found with a
> respectable frequency as the size of the dataset grows (C Robert
> discusses this in a preprint in arxiv see
> http://arxiv.org/PS_cache/arxiv/pdf/1002/1002.2080v1.pdf ) So even
> though you could check each individual point for normality, testing
> the whole dataset requires that you apply a Bonferoni correction to
> your z.tests or use outlier.test from package "car" to reduce the
> amount of code you have to write.
>
>
>
> Regards,
>
> Christos
>
> > Date: Fri, 16 Apr 2010 19:11:19 +0300
> > From: attenka at utu.fi
> > To: r-help at r-project.org
> > Subject: [R] Is it ok to apply the z.test this way?
> >
> > Dear R-users,
> >
> > I want to check if certain values are from random distribution, that
> includes values between 0-1. So, it is not really normal even though
> shapiro.test says it is highly normal... Can I do something like this
> and think that the values given are right. z.test is from package
> TeachingDemos.
> > -------------------------------------------------------------------------------
> > SelectedVals=c()
> > for(i in seq(0,1,by=0.001))
> > {
> > if((z.test(i, mu=mean(Distribution),
> stdev=sd(Distribution))$p.value)<=0.05) SelectedVals=c(SelectedVals,i)
> > }
> >
> > -------------------------------------------------------------------------------
> > I have marked the border values given by this script to the
> histogram of the original random distribution:
> >
> > http://www.ag.fimug.fi/~Atte/62Hist100410.pdf
> >
> > Atte Tenkanen
> > University of Turku, Finland
> > Department of Musicology
> > +35823335278
> > http://users.utu.fi/attenka/
> >
> > ______________________________________________
> > 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.
>
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