>
>At 05:48 PM 9/20/2001 +0000, you wrote:
>>I am trying to solve a ? which basically gives the following facts:
>>
>>population of unknown number
>>popu std dev of 27
>>pop mean of 78
>>sample of size n=81
>>2000 random samples
>>
>>The ? is:
>>
>>what is the sample mean?
>>what is the std error (std dev of sample means)
>>what shape would the histogram be?
>>
>>The sample mean is obviously 78 and I calculate the std error of the sample
>>means to be 3.
>>
>>However I can't put the whole picture together. I suspect the distrib would
>>be normal given the 81 samples, but is 3 a low number for a std error.
>
>2000 samples of size 81 according to info you provided; and sample
>standard deviation should be
>smaller than population standard deviation according to central limit theorem.
>
>
>>Is it possible to translate it into a z score without any addtional data.
>>
>>Also I assume that the population itself could take any form skewed, normal
>>etc and you still end up w/the same std deviation.
>
>All possible
>
>
>>In other words is the std deve of 27 and mean of 81 in any way predictive of
>>what a histogram of a distribution would look like?
>>
>>Finally what difference does it make how many random samples you take (ie.
>>100 or 1000). What statistic or parameter does this speak to?
>
>The sampling distribution will always approximate a normal distribution
>regardless of the shape of the
>population distribution -- again, the central limit theorem.
>
>hope his helps........... ECD
>
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>
>___________________________
>Edward C. Dreyer
>
>Political Science
>The University of Tulsa
>
>
___________________________
Edward C. Dreyer
Political Science
The University of Tulsa
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