Re: [R] shapiro wilk normality test

From: Marta Colombo <martaepelosi_at_yahoo.it>
Date: Sun, 13 Jul 2008 11:20:54 +0000 (GMT)


Hi!
Well, if you look at the output:
shapiro.test(rnorm(5000))
>
>        Shapiro-Wilk normality test
>
> data:  rnorm(5000)
> W = 0.9997, p-value = 0.6205

You can see that the p-value is 0.6205 so you can't refuse the normality hypotesis. H0: normal data    vs H1: not normal
So shapiro.wilk test is saying that your data are normal and it's correct! Bye

Marta

You may consider the nortest package.

http://cran.r-project.org/web/packages/nortest/index.html

Regards,

CH

On Sat, Jul 12, 2008 at 11:30 PM, Bunny, lautloscrew.com <bunny_at_lautloscrew.com> wrote:
> Hi everybody,
>
> somehow i dont get the shapiro wilk test for normality. i just can´t find
> what the H0 is .
>
> i tried :
>
>  shapiro.test(rnorm(5000))
>
>        Shapiro-Wilk normality test
>
> data:  rnorm(5000)
> W = 0.9997, p-value = 0.6205
>
>
> If normality is the H0, the test says it´s probably not normal, doesn´t it ?
>
> 5000 is the biggest n allowed by the test...
>
> are there any other test ? ( i know qqnorm already ;)
>
> thanks in advance
>
> matthias
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>

-- 
CH Chan
Research Assistant - KWH
http://www.macgrass.com
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Received on Sun 13 Jul 2008 - 11:26:37 GMT

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