[R] alternative option in skewness and kurtosis tests?

[peter dalgaard]

On Oct 25, 2011, at 18:23 , Xiang Gao wrote:

> I have a question about the D'Agostino skewness test and the Anscombe-Glynn
> kurtosis test.
> 
> 
> agostino.test(x, alternative = c("two.sided", "less", "greater"))
> 
> anscombe.test(x, alternative = c("two.sided", "less", "greater"))
> 
> The option "alternative" in those two functions seems to be the null
> hypothesis. In the output, the statement about the alternative hypothesis is
> correct, which is opposite to what you specify in command. An example
> below:

Certainly looks like a bug. You should contact the maintainers of the contributed package containing these tests. 

-pd


> 
> 
> 
>> skewdata =
> c(rep(44,5),rep(43,15),rep(42,10),rep(41,4),rep(40,3),rep(39,2),rep(38,1))
> 
>> agostino.test(skewdata, alternative = "greater")
> 
>        D'Agostino skewness test
> 
> data:  skewdata
> 
> skew = -1.0014, z = -1.7209, p-value = 0.04264
> 
> alternative hypothesis: data have negative skewness
> 
> 
>> anscombe.test(skewdata,  alternative=„less")
> 
>        Anscombe-Glynn kurtosis test
> 
> data:  skewdata
> 
> kurt = 3.4748, z = 1.0716, p-value = 0.1419
> 
> alternative hypothesis: kurtosis is greater than 3
> 
> 
> --
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com