Re: Tests for randomness

In article <1129446141.286800.78800@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
<Stugrad98@xxxxxxx> wrote:
>Hi,

>If I have a set of data points (14 to be exact) with an unknown
>pedigree from a large population, what tests can I apply to see if they
>constitute a random sample?

>In a related question: if I knew a priori that the larger population
>fell along a general distribution (say lognormal) and if a lognormal
>line plot of this sub-data (14 points, unknown pedigree) fit rather
>snugly, could I safely assume that my 14 data points were randomly
>selected? Or would I be making a potentially damaging assumption?

With 14 points, only huge differences from randomness
can be detected. If the fit is quite good, the better
conclusion might well be that the points were selected
to give a stratified sample, not a random sample.
--
This address is for information only. I do not claim that these views
are those of the Statistics Department or of Purdue University.
Herman Rubin, Department of Statistics, Purdue University
hrubin@xxxxxxxxxxxxxxx Phone: (765)494-6054 FAX: (765)494-0558
.

Relevant Pages

  • Tests for randomness
    ... If I have a set of data points (14 to be exact) with an unknown ... pedigree from a large population, what tests can I apply to see if they ... constitute a random sample? ...
    (sci.stat.edu)
  • Tests for randomness
    ... If I have a set of data points (14 to be exact) from a large population ... whose pedigree I'm unsure of, what tests can I apply to see if they ... constitute a random sample? ...
    (sci.stat.consult)