I'd also like to point out that, even though I am not familiar with how SPSS
and other stat packages calculate these things, I'm guessing they do it via
a "simple frequency distribution" rather than a "grouped frequency
distribution". That could/might account for small differences in the hand-
vs. computer-calculated answers.
--Cheryl
------------------------------------------------------------
>"G. Marc Turner" wrote:
>
> > I need some advice on how to handle an issue in my stats course...
> >
> > I'm currently using the Essentials of Statistics (by Gravetter &
>Wallnau) as the textbook. In the chapter on variability, it uses the real
>limits for the calculation of the range, inter-quartile range, etc. This is
>actually how I learned to do the calculations by hand, and haven't really
>thought much about it until now. <snip>
> > I'm also teaching the students how to use SPSS (v9) to get the same
information after going over the hand-calculations. BUT, SPSS does not use
the real limits when calculating the range, quartiles, etc. (For example,
for one data set we get a range of 9 and an interquartile range of 1.89 by
hand. SPSS calculates the range as 8 and the interquartile range as 2.)
> I don't mess with the upper and lower limits anymore (except when I
>teach them how to graph). I don't think it's worth the effort. With a
>_small_ data set, knowing that the IQR is 3.1 as opposed to 3.0 is rarely
>useful. <snip>
>John W. Kulig
************************************************************
Cheryl Schwartz, Ph.D.
[EMAIL PROTECTED]
OR
[EMAIL PROTECTED]
--------------------------------------------------
If logic is in the eye of the logician,
then is wit in the eye of the wittician?
************************************************************
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