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From "Piotr KochaƄski" ...@uw.edu.pl>
Subject [math] Re: "Straw man" release plan
Date Tue, 03 Feb 2004 10:58:47 GMT
Mark R. Diggory wrote:

<cut/>
> 
> 
> I think maybe this should be returning the more generic 
> StatisticalSummary interface. If you are returning precalculated 
> results, you do not exactly want to expose the underlying implementation 
> to modification by the user.
> 
> StatisticalSummary[] sampleStats ...

That's good idea
 

> If your going to be preserving the original/bootstrap values in a 
> double[][], then the Standard "DescriptiveStatisticsImpl" could be used.
> 
> public interface FullStatisticalSummary {
> 	public abstract double getMean();
> 	public abstract double getVariance();
> 	public abstract double getStandardDeviation();
> 	public abstract double getMax();
> 	public abstract double getMin();
> 	public abstract long getN();
> 	public abstract double getSum();
> 	public abstract double getPercentile(double p);
> 	...
> }
> 
> or more simply,
> 
> public interface FullStatisticalSummary extends StatisticalSummary{
> 	public abstract double getPercentile(double p);
> 	...
> }

Exactely, but the point is that we have to preserve original/bootstrap
values and EmpiricalDistribution is not storing them - internally it keeps
data
in the array of bins. As I understand this was the aim - we don't have to
keep the whole data set in order to get important information about the
empirical distribution.  If a data set is huge this is a true gain.

If, on the other hand, I want to keep the whole data set then I can easily
use
other tools to calculate any statistics I want so I don't need to use 
EmpiricalDistribution.

Documentation for EmpiricalDistribution gives two example applications
of this interface - preparing data for drawing a histogram and provide
methods to draw random numbers from such a distribution. I am
wondering if making EmpiricalDistribution responsible for other tasks
like handling bootstrap samples or even doing bootstrap would not
make it to complicated to use.

Piotr


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