the only purpose it can serve ... and i am not saying this is important ...
is to know that the median is part of a boxplot ... just like you might
want them to identify what the | are at the ends ... the hinges ... just as
you might want them to know that the whisker has 25% in it ... at each end ...
now, what might be important from my view:
1. be able to differentiate it from say .. a histogram ... or other graphic
display
2. that the distance from the end of each whisker ... represents the range
of data
3. that the bar in the middle indicates something about "average"
4. that patterns with short a short whisker at one end and a long whisker
at the other end ... tell you something about the shape not being symmetrical
bottom line:
there are thousands of items one can create and ask ...
lots of these are totally unimportant
each item that goes on a test that has some import ... should be seen as
being an important fact/idea to be testing
whether the item you talk about rises to the level of being important
enough ... i am not sure ... certainly, in the overall scheme of things ...
IF it is included ... it would have to be considered to be of trivial value
... and if someone misses it ... they should not be docked as much as many
other more fundamentally important items ... that hopefully WILL be put on
the test
At 02:17 PM 8/25/01 +0000, EugeneGall wrote:
>Some of the MCAS stats and probability questions were tough but fair. I
>disagreed vehemently with one question:
>Question 39 on the 10th grade Math 2001 test.
>It showed a Tukey boxplot and asked whether the graph represented a mean and
>range or a median and range.
> Now, this question will do one thing. It will separate the rich school
>districts that have purchased the latest texts which include a description of
>the boxplot from older texts (listed on the MCAS curriculum guideline)
> As a college prof, I can state that none of my texts circa 1976-1980
> included
>descriptions of the boxplot. Many still do not (e.g., Larsen & Marx Intro to
>Math stats 2001)
> I think Tukey could just as well have chosen the mean for his display
> method.
> In scientific talks, even today, one must tell the audience that the bar
>indicates the median not the mean.
> So if the problem isn't in the texts, probably wasn't taught to the
> teachers,
>and never appears in the popular press and is even rare in the scientific
>literature, why put it as one of the handful of test items?!!!
> What purpose does a question like this serve????
>
>http://www.doe.mass.edu/mcas/01release/
>
>
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==============================================================
dennis roberts, penn state university
educational psychology, 8148632401
http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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