[R] shapiro.test

[Greg Snow]

Rui,

Note this quote from the last paragraph of the Details section of ?ks.test:

"If a single-sample test is used, the parameters specified in '...'
     must be pre-specified and not estimated from the data."

Which is the exact opposite of your example.



Gonzalo,

Why are you testing your data for normality?  For large sample sizes
the normality tests often give a meaningful answer to a meaningless
question (for small samples they give a meaningless answer to a
meaningful question).

If you really feel the need for a p-value then
SnowsPenultimateNormalityTest in the TeachingDemos package will work
for large sample sizes.  But note that the documentation for that
function is considered more useful than the function itself.



On Fri, Feb 21, 2014 at 3:04 PM, Rui Barradas <ruipbarradas at sapo.pt> wrote:
> Hello,
>
> Not answering directly to your question, if the sample size is a documented
> problem with shapiro.test and you want a normality test, why don't you use
> ?ks.test?
>
> m <- mean(HP_TrinityK25$V2)
> s <- sd(HP_TrinityK25$V2)
>
> ks.test(HP_TrinityK25$V2, "pnorm", m, s)
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 21-02-2014 15:59, Gonzalo Villarino Pizarro escreveu:
>
>> Dear R users,
>> Please help with with this maybe basic question. I am trying to see if my
>> data is normal but is a large file and the test does not work.
>> I keep getting the message : "Error in shapiro.test(x = HP_TrinityK25$V2)
>> :  sample size must be between 3 and 5000"
>> thanks!
>>
>>   shapiro.test(x=HP_TrinityK25$V2)
>> Error in shapiro.test(x = HP_TrinityK25$V2) : sample size must be between
>> 3
>> and 5000
>>
>> ##Note:
>> HP_TrinityK25= my file
>> HP_TrinityK25$V2= data in my file
>>
>>         [[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.
>>
>
> ______________________________________________
> 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.



-- 
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com