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Science Forum Index » Statistics - Math Forum » wanting to figure out a distribution...
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 Posted: Fri Jul 18, 2008 2:34 pm |
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so i know the following information for a distribution of test
scores...the mean is 229, the median is 221, the std dev is 20, the
sample size is a 180 students. is it possible to get a function for a
distribution based on this information...or at least figure out the
scores for each percentile?
if not, what add'l info would i need to answer these questions. thanks
so much for your help. |
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| Herman Rubin... |
| Posted: Sat Jul 19, 2008 1:40 pm |
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In article <5751d903-26d6-4fe8-bbf0-6bc05035693e at (no spam) y38g2000hsy.googlegroups.com>,
<rajamohan82 at (no spam) gmail.com> wrote:
Quote: so i know the following information for a distribution of test
scores...the mean is 229, the median is 221, the std dev is 20, the
sample size is a 180 students. is it possible to get a function for a
distribution based on this information...or at least figure out the
scores for each percentile?
if not, what add'l info would i need to answer these questions. thanks
so much for your help.
From a finite number of pieces of information like this, there
is no way to figure out the distribution. In fact, one could
put 25/29 of the distribution at 221, and the remainder at 270,
and achieve that mean, median, and standard deviation.
To answer those questions, one needs to look at the actual
distribution, or assume a form and fit parameters.
--
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 at (no spam) stat.purdue.edu Phone: (765)494-6054 FAX: (765)494-0558 |
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