what about if n is only 15 and the population distribution is heavily
skewed? Isn't there a balancing here. Of course w/81 samples, it is hard to
conceive anything but a normal distrib based on the CLT.
"Edward Dreyer" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
>
> >
> >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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