Nancy:
I would teach them both. I would use this case as a simple example of
the first step in using statistics. The first step is to decide what is
your question. Are you trying to describe your sample or you trying to
make an inference about a population? You can strengthen this point in
the exercises by asking the students what is the question of interest in
each exercise and what is the appropriate formula to use in that case.
Ken
[EMAIL PROTECTED] wrote:
Hello,
My whole academic life I have been doing the standard deviation
calculation with a denominator of N-1. Everybook I've used has this as
the formula at least for the sample version (as opposed to the
population version), all my notes and powerpoints make reference to
this, and as far as I can see, SPSS uses this formula (and I am using
SPSS in my class).
My new stats class is underway and now that I look carefully at the book
(Aron et al) I see that their version of this formula is done with a
denominator of N, which in my opinion causes a underestimation of
dispersion and (for fact) will make my life a living hell if I choose to
go with it.
So I am leaning toward instructing the students to ignore this formula
and use mine. It means that I will not be able to use many of the
practice problems in the book (but I have plenty of others to use) and
might cause them some small amount of confusion. I will probably have to
remind them periodically. Am I being selfish or unfair in trying to make
my life easier this way?
And can someone tell me why most all statistics books have some feature
or formula that is an idiosyncratic version? It almost seems like things
are done whimsically. I've encountered this with percentiles, stem and
leaf and other concepts. This is just the worst one so far.
Nancy Melucci
Long Beach City College/CSULA
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--
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Kenneth M. Steele, Ph.D. [EMAIL PROTECTED]
Department of Psychology http://www.psych.appstate.edu
Appalachian State University
Boone, NC 28608
USA
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