[R] test for whether dataset comes from a known MVN

[Desmond Campbell]

Dear Ben Bolker,

 

Thanks for replying and offering advice, unfortunately it doesn't solve my 
problem.

1) The mshapiro.test() in the mvnormtest package appears only applicable 
for datasets containing 3-5000 samples, whereas my dataset contains 100,000 
samples.

2) As you said in your email if my data is from the real world then any 
test is likely to reject the null hypothesis, because of the power of such a 
large dataset.

However my data is not from the real world. I am conducting validation 
studies, and if the program I am testing is working correctly then the dataset 
will be perfectly normally distributed.

Thanks anyway.

 

regards

Desmond Campbell

 

 

> Campbell, Desmond wrote:
> 
> Dear all,
> 
> I 
have a multivariate dataset containing 100,000 or more points.
> I want 
find the p-value for the dataset of points coming from a
> particular 
multivariate normal distribution
> With
> mean vector u
> 
Covariance matrix s2
> So
> H0: points ~ MVN( u, s2)
> H1: 
points not ~ MVN( u, s2)
> How do I find the p-value in R?
> 



> Ben Bolker wrote: 

> >    Googling for "Shapiro-Wilk multivariate" brings up 
mshapiro.test()
> > in the mvnormtest package.  However, I would 
strongly suspect that
> > if your data are from the real world that you 
will reject the null
> > hypothesis
> > of multivariate 
normality when you have 100,000 points -- the power
> > to detect tiny 
(unimportant?) deviations from MVN will be very 
high.
> > 
> >   cheers
> >     Ben Bolker
 
It's about the oil, stupid!
                                         ("`-/")_.-'"``-._
                                           . . `; -._    )-;-,_`)
                                          (v_,)'  _  )`-.\  ``-'
                                         _.- _..-_/ / ((.'
                                       ((,.-'   ((,/




      ___________________________________________________________ 
Want ideas for reducing your carbon footprint? Visit Yahoo! For Good  http://uk.promotions.yahoo.com/forgood/environment.html