[R] one-sample binomial test
A.J. Rossini
rossini at blindglobe.net
Mon Jul 8 05:55:33 CEST 2002
I've got two minds on this. On the positive side, it's nice to see an
intro student actually try to substitute R for SPSS and similar
point-and-quite-possibly-shoot-yourself-in-the-foot packages.
Secondly, trial and error IS how most people figure it out, at the
very basic level, and using R as a calculator is one way to do it.
Numerical (and statistical) approximations and simulation lie at the
heart of the best sample size calcs, though it takes a long, long time
to appreciate the full ramifications of this :-). Go Tim! You've got
a long way to go...
However, as friendly and useful as some of the responses and
respondents can be, for better or worse, this isn't quite an
appropriate list for statistics help, so I do sympathize with Rolf.
best,
-tony
>>>>> "andrew" == Andrew C Ward <andreww at cheque.uq.edu.au> writes:
andrew> This reply, while probably seen as helpful by some, reminds me that
andrew> sometimes the price paid for "free" software is to endure rude, patronising
andrew> interactions with some of those in the user or developer community.
andrew> Tim Wilson originally wrote:
>>> Here's how I solved a problem for my stats class. I'm pretty sure I
>>> understand what's going on, but I wonder if there's a more direct way
>>> to solve it.
andrew> Rolf Turner replied:
>> (a) You definitely don't have to --- and SHOULDN'T --- use ``trial
>> and error''.
>> (b) You should talk to the instructor of your stats class. That's
>> what he or she is paid for.
>> (c) You should also read your textbook.
>> (d) This is a very standard sort of problem. It is also very easy to
>> solve with pencil and paper (or at the very least a hand
>> calculator). You do ***not*** need to use binom.test() (in fact this
>> is counter productive) nor do you need to use prop.power.test() as
>> someone else suggested (although this will do it for you).
>> There is a formula for the required sample size which is surely given
>> in your textbook --- in ***any*** introductory stats textbook. The
>> formula is readily amenable to use with ``hand calculations''. Find
>> the formula and use it.
>> (e) You were given this exercise to get you to learn some of the
>> basic ideas about confidence intervals for proportions. Learn them.
>> Don't try to dodge the issue by pumping numbers through a
>> computerized ``black box''.
andrew> Regards,
andrew> Andrew C. Ward
andrew> CAPE Centre
andrew> Department of Chemical Engineering
andrew> The University of Queensland
andrew> Brisbane Qld 4072 Australia
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--
A.J. Rossini Rsrch. Asst. Prof. of Biostatistics
U. of Washington Biostatistics rossini at u.washington.edu
FHCRC/SCHARP/HIV Vaccine Trials Net rossini at scharp.org
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