Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Kairavi Bhakta
> Sent: Friday, June 10, 2011 11:24 AM
> To: r-help at r-project.org
> Subject: [R] Test if data uniformly distributed (newbie)
>
> Hello,
>
> I have a bunch of files containing 300 data points each with values
> from 0
> to 1 which also sum to 1 (I don't think the last element is relevant
> though). In addition, each data point is annotated as an "a" or a "b".
>
> I would like to know in which files (if any) the data is uniformly
> distributed.
>
> I used Google and found out that a Kolmogorov-Smirnov or a Chi-square
> goodness-of-fit test could be used. Then I looked up ?kolmogorov and
> found
> "ks.test", but the example there is for the normal distribution and I
> am not
> sure how to adapt it for the uniform distribution. I did ?runif and
> read
> about the uniform distribution but it doesn't say what the "cumulative
> distribution" is. Is it "punif", like "pnorm"? I thought of that
> because I
> found a message on this list where someone was told to use "pnorm"
> instead
> of "dnorm". But the help page on the uniform distribution says punif is
> the
> "distribution function". Are the "cumulative distribution" and the
> "distribution function" the same thing? Having several names for the
> same
> thing has always confused me very much in statistics.
>
> Also, I am not sure whether I need to specify any parameters for the
> distribution and which. I thought maybe I should specify "min=0" and
> "max=1"
> but those appear to be the defaults. Do I need to specify q, the vector
> of
> quantiles?
>
> So is
> > ks.test(x, punif)
> correct or not for what I am attempting to do?
>
> After this I will also need to find out whether the a's and b's are
> distributed randomly in each file. I would be greatful for any pointers
> although I have not researched this issue yet.
>
> Kairavi.
>
> [[alternative HTML version deleted]]
>
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