Re: Kolmogorov-Smirnov test and duplicates...

[E. Jacquelin Dietz]

I'm sure it is not correct to remove observations that equal other 
observations in the Kolmogorov-Smirnov one-sample test.  See, for 
instance, Applied Nonparametric Statistics (2nd edition) by Wayne 
Daniels, where there is an example starting on page 321 that contains 
many ties.  Nonparametric Statistical Methods (2nd edition) by Hollander 
and Wolfe has two equations for D on page 530 -- Equation 11.108 for the 
case where the observations are distinct, and Equation 11.110 where 
there are tied observations.

Jackie Dietz

Michael wrote:
Reference?  What do you mean by "removing
duplicates"  and what is this K-S  test about?


I am testing goodness-of-fit for continuous distributions.

I have been taught to delete any duplicate data points for example if
we have 10,33,44,44,44,44,55,56 I would calculate my sample and
theorectical probabilites then delete all but ONE of the 44's (the
duplicate data points) and the calculate the differences and then find
then take the absolute values of the differences and my D-value is the
largest of those.
The question is which ONE do leave behind? Its a choice that has an
impact on the resulting D-value.
The dataset I am working almost halves in size when I remove the
duplicates, I have a lot of measurments that are the same. I am
testing the goodness-of-fit of the data to see if it's distrobution is
Gamma (or one of its special cases).
I hope the description of what I'm doing makes sense. 

What method do you use to test goodness-of-fit for coninuous
distributions?
Thanks in advance
Michael
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