[R] normality test

[Pieter Provoost]

----- Original Message -----
From: "Romain Francois" <francoisromain at free.fr>
To: "Pieter Provoost" <pieterprovoost at gmail.com>; "RHELP"
<R-help at stat.math.ethz.ch>
Sent: Thursday, April 28, 2005 2:03 PM
Subject: Re: [R] normality test


> Le 28.04.2005 13:16, Pieter Provoost a écrit :
>
> >Hi,
> >
> >I have a small set of data on which I have tried some normality tests.
When I make a histogram of the data the distribution doesn't seem to be
normal at all (rather lognormal), but still no matter what test I use
(Shapiro, Anderson-Darling,...) it returns a very small p value (which as
far as I know means that the distribution is normal).
> >
> >Am I doing something wrong here?
> >Thanks
> >Pieter
> >
> >
> Hello,
>
> You seem to know not far enougth.
> Null hypothesis in shapiro.test is **normality**, if your p-value is
> very small, then the data is **not** normal.
>
> Look carefully at ?shapiro.test and try again. Furthermore, normality
> tests are not very powerful. Consider using a ?qqnorm and ?qqline
>
> Romain

Thanks, I thought null hypothesis for these tests was "no normality"...

Pieter