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-help immed-, -sampsi- or -prtesti-?
HTH
Martin
_______________________
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Wednesday, March 25, 2009 7:05 PM
Subject: st: binary proportions and sample size
This is stupid question stemming from a practical problem. The problem
sounds easy and familiar, but I don't have a statistical manual at hand
and no idea about the keywords to refine a search for the solution on
Statalist.
I took a (let's say random) sample of 74 tools from a popolation of 900. I
checked personally each of the 74 tools, and found that 4 of them have
some problems (5,4%) and 70 are ok. Can I expect to find 49 (5,4% x 900)
problems in the population (i.e. is the sample size big enough to say so)
and can I attach a p-value to my expectations (i.e. which is the
probability that the problem-rate in the sample and in the population are
different - statistically significantly different)? (And, obviously, which
Stata command will answer to my questions???)
Many thanks in advance for your help,
Nicola
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* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
