commons-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Kim van der Linde <kimvdli...@yahoo.com>
Subject Re: [math] Only sample variances?
Date Mon, 16 Aug 2004 11:47:01 GMT
Hi MArk,

I think we have to think very carefully about this.
Especially when we start including covariances. My old
textbooks give the formula as population estimates,
just like excell (no choice, only population).
However, covariance matrices include the sample
covariances....

Cheers,

Kim
--- "Mark R. Diggory" <mdiggory@latte.harvard.edu>
wrote:

> Yes, at the UnivariateStatistic level, these would
> need to be new 
> classes. My question as well is "Does it apply as
> well to higher order 
> moments?"
> 
> Maybe we should place everything into the following
> packages:
> 
> o.a.c.m.stat.univariate.moment.sample
> o.a.c.m.stat.univariate.moment.population
> 
> -Mark
> 
> Phil Steitz wrote:
> 
> > Kim van der Linde wrote:
> > 
> >> Hi,
> >>
> >> I just looked through the variance class, and saw
> that
> >> it only supports sample vasriance (N-1) but not
> >> population variances (N). Any reason for this,
> and can
> >> it be added?
> > 
> > 
> > It would probably be better to add this to one of
> the aggregates or 
> > StatUtils or to add a new statistic altother. This
> is because a 
> > UnivariateStatistic can only report one value. The
> most commonly used 
> > (at least in statistical applications) value for
> Variance and Standard 
> > Deviation is the sample statistic, which is why
> that is what the 
> > statistics named "StandardDeviation" and
> "Variance" report. From a 
> > user's perspective, its not too hard to convert;
> but I agree that it 
> > would be convenient to add these. Probably best to
> make new statistics 
> > in the moment subpackage called "PopulationXxx". 
> Patches welcome ;-)
> > 
> > Phil
> > 
> > 
> >>
> >> Cheers,
> >>
> >> Kim
> >>
> >>
> >>        
> >> __________________________________
> >> Do you Yahoo!?
> >> Yahoo! Mail - 50x more storage than other
> providers!
> >> http://promotions.yahoo.com/new_mail
> >>
> >>
>
---------------------------------------------------------------------
> >> To unsubscribe, e-mail:
> commons-dev-unsubscribe@jakarta.apache.org
> >> For additional commands, e-mail:
> commons-dev-help@jakarta.apache.org
> >>
> > 
> > 
> >
>
---------------------------------------------------------------------
> > To unsubscribe, e-mail:
> commons-dev-unsubscribe@jakarta.apache.org
> > For additional commands, e-mail:
> commons-dev-help@jakarta.apache.org
> > 
> 
> -- 
> Mark Diggory
> Software Developer
> Harvard MIT Data Center
> http://www.hmdc.harvard.edu
> 
>
---------------------------------------------------------------------
> To unsubscribe, e-mail:
> commons-dev-unsubscribe@jakarta.apache.org
> For additional commands, e-mail:
> commons-dev-help@jakarta.apache.org
> 
> 



		
__________________________________
Do you Yahoo!?
Yahoo! Mail Address AutoComplete - You start. We finish.
http://promotions.yahoo.com/new_mail 

---------------------------------------------------------------------
To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-dev-help@jakarta.apache.org


Mime
View raw message