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Re: IA Regents #37 perimeter
Posted:
Jun 26, 2008 8:30 PM
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I absolutely cannot follow this argument. Sorry. How can a walkway involve anything else but area? Even in the case mentioned a while back by somebody about buying rectangular blocks for the walkway at Home Depot, you need to know the area of the ground to be covered or, at least, the dimensions of the space to be covered. How this could lead to perimeter instead of area is beyond me. Moreover, if the student used perimeter (conceptual error) and then followed that with an incorrect solution (of an incorrect equation), I fail to see that anything is correct.
Bobbi Eisenberg
-----Original Message-----
From: msedfun@aol.com
To: nysmathab@mathforum.org
Sent: Wed, 18 Jun 2008 8:21 am
Subject: Re: IA Regents #37 perimeter
We have decided to score this problem as follows:
If the student found perimeter, and clearly indicated the correct formula, but solved incorrectly, we awarded 1 point. If the student found perimeter, clearly indicated the correct formula, and solved for the variable correctly, we awarded 2 points.
I definitely agree that a walkway should indicate perimeter rather than area because it stated you are 'constructing' a walkway, not its floor, and you would be making an area with an obvious opening such as a tunnel. In such a case, you would not be filling it in, and therefore, despite the information regarding the units which could have clued the student to an area solution, it was unclear. This is yet another case of very poor problem construction. Maybe some non-math teachers should be going over regents problems before they are settled upon in order to identify these inconsistencies.
Sharon <----who is very unpleased with the way this new regent was formed, and the new IA course in general
The rubric says 2 points for one
conceptual error. So we gave 2 points to a correct perimeter solution
(with both length and width stated.) The rubric says nothing about more
deductions for an easier solution (is that a remnant from previous scoring
guidelines?) In addition, since a number of our students solved the
quadratic with guess and check, a linear solution is not necessarily easier.
Perimeter instead of area is an OBVIOUS
error that I think the rubric should have addressed directly. A number of
students told me later that they thought a walkway went around something and so
this was a perimeter problem. Calling it a walkway was a distraction. Using
only the units to ask for area was too subtle.
-----Original Message-----
From: Meg Clemens <mclemens@twcny.rr.com>
To: nysmathab@mathforum.org
Sent: Wed, 18 Jun 2008 5:32 am
Subject: RE: IA Regents #37 perimeter
The rubric says 2 points for one
conceptual error. So we gave 2 points to a correct perimeter solution
(with both length and width stated.) The rubric says nothing about more
deductions for an easier solution (is that a remnant from previous scoring
guidelines?) In addition, since a number of our students solved the
quadratic with guess and check, a linear solution is not necessarily easier.
Perimeter instead of area is an OBVIOUS
error that I think the rubric should have addressed directly. A number of
students told me later that they thought a walkway went around something and so
this was a perimeter problem. Calling it a walkway was a distraction. Using
only the units to ask for area was too subtle.
We gave 0 credits to the sum of two sides.
We considered this method to contain two conceptual errors: using
perimeter instead of area and not determining perimeter correctly. Given
the work shown, I don?t see how you could deduce that a student who added
two sides knew the problem was area but thought area was the sum instead of the
product. I think it far more likely that they were doing perimeter
incorrectly. Since the work doesn?t allow me to see the difference
between these methods, I feel I can not assume more knowledge than shown.
However, I?m willing to be convinced otherwise?it would gain an
extra point or two for a LOT of students. If
you feel you can convince me, please do it quickly ;)
Meg Clemens
Canton NY
From: owner-nysmathab@mathforum.org [mailto:owner-nysmathab@mathforum.org] On Behalf Of msedfun@aol.com
Sent: Tuesday, June 17, 2008 11:14
PM
To: nysmathab@mathforum.org
Subject: Re: IA Regents #37
perimeter
I want to make sure I understand how you are scoring this
question. If a student has found perimeter instead of area, you are
calling it a conceptual error and awarding one point. If you set up the
perimeter formula according to the problem you will generate the following
formula: 2(x) + 2(x+15) = 54. Your answer will then be x = 6. Are
you crediting this with 1 point? Please let me know, because we have
scored it as 0.
Sharon :)
We decided 1 pt for either (semi perimeter OR perimeter
equations solved and followed through correctly). Both attempts could
reasonably represent one conceptual error (either the student thought the
sum could be used to find the area or the student confused area and perimeter)
AND this error results in a substantially easier problem. Giving 2 points
for a perimeter solution ignores the fact that the problem is substantially
simplified by this error.
-----Original
Message-----
From: Thomas Mariano <tjmariano@hotmail.com>
To: nysmathab@mathforum.org
Sent: Tue, 17 Jun 2008 8:34 pm
Subject: RE: IA Regents #37 perimeter
We decided 1 pt for
either (semi perimeter OR perimeter equations solved and followed through
correctly). Both attempts could reasonably represent one conceptual error
(either the student thought the sum could be used to find the area or the
student confused area and perimeter) AND this error results in a substantially
easier problem. Giving 2 points for a perimeter solution ignores the fact
that the problem is substantially simplified by this error.
Tom Mariano
> Date: Tue, 17 Jun 2008 16:47:42 -0400
> From: kline715@verizon.net
> Subject: Re: IA Regents #37
> To: nysmathab@mathforum.org
>
> I graded that question and ended up with a lot of 1's because they added
> the length and the width. They didn't even find the perimeter. One
> student did the perimeter and we gave it 2.
>
> TKENYON@crcs.wnyric.org wrote:
> > #37: what if they do perimeter instead of area?? 1 conceptual
> > error = 2 points?
> > We're trying to decide if it's worth 2 points or 1 point.
> >
> > -Tom
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