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# Re: st: How do I demonstrate that a sample is randomly drawn from a population?

 From Yuval Arbel To David Greenberg Subject Re: st: How do I demonstrate that a sample is randomly drawn from a population? Date Sun, 14 Apr 2013 14:14:07 -0700

```David, thanks for your answer. As I noted in my question - I already
tried the difference-of-mean test. I'm not sure, however, this is the
appropriate test for the problem I presented (in your answer - you
said the same thing in different words).

My educated guess would be - that to demonstrate a random sample - I
need to make some comparison between the population and sample
distribution. The question would still be what exact test do I need -
and what is the appropriate command in stata

On Sun, Apr 14, 2013 at 1:56 PM, David Greenberg <dg4@nyu.edu> wrote:
> Testing whether the mean of a sample is significantly different from the
> mean of a population is a topic covered in every introductory statistics
> book. However, even if the differences in means is not statistically
> significant,  you still have not demonstrated that the sample was, in fact,
> randomly drawn from the given population. David Greenberg, Sociology
> Department, New York University
>
>
> On Sun, Apr 14, 2013 at 3:00 PM, Yuval Arbel <yuval.arbel@gmail.com> wrote:
>>
>> Dear statalisters,
>>
>> I have two files:
>>
>> 1) The first file contains the grades of all population of Open
>> University students.
>>
>> 2) The second file contains the grades of Open University students,
>> who filled a questionnaire via the net.
>>
>> I would like to show that the second file is a random sample drawn
>> from the first file.
>>
>> The question is can I provide a statistical evidence that the sample
>> is indeed random? what are the appropriate commands in stata?
>>
>> P.S. I thought to run the test of difference of means between two
>> populations. Having reconsidered, however, I'm not talking here about
>> two populations, but rather a sample,which is drawn from a given
>> population.
>>
>>
>> --
>> Dr. Yuval Arbel
>> 4 Shaar Palmer Street,
>> Haifa 33031, Israel
>> e-mail1: yuval.arbel@carmel.ac.il
>> e-mail2: yuval.arbel@gmail.com
>> *
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>
>

--
Dr. Yuval Arbel