# [LON-CAPA-users] Unordered Response Question Error

Harding, Gene L glhardin at purdue.edu
Wed Jan 25 08:24:34 EST 2017

```Hi Carl,

Thank you for sending that. As it turns out, in this particular problem the answers are integers and a tolerance of zero works, but I will definitely keep that in mind in the future.

BR,

Gene L. Harding, PE
Associate Professor of ECET
574-520-4190
Purdue University-South Bend

From: lon-capa-users-bounces at mail.lon-capa.org [mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Carl Lira
Sent: Tuesday, January 24, 2017 8:16 PM
To: 'Discussion list for LON-CAPA users' <lon-capa-users at mail.lon-capa.org>
Subject: Re: [LON-CAPA-users] Unordered Response Question Error

I don't see the script, but you need to have a tolerance. When the value is not specified, it defaults to an absolute tolerance of zero. If a floating point calculation is done, it will never be exactly an integer. From the author manual:

A tolerance parameter determines how closely the system will require the student's
answer to be in order to count it correct. The tolerance will default to zero if it is not
defined. The tolerance parameter should always be defined for a numerical problem
unless you are certain only integer answers are generated from your script and you
want students to reply with exactly that integer.
If the computer answer is a floating point number, the tolerance should not be zero.
Computers can only approximate computations involving real numbers. For instance,
a computer's [decimal] answer to the simple problem 1
3 is "0.33333333333333331". It
should be an infinite series of 3's, and there certainly shouldn't be a "1" in the an-
swer, but no computer can represent an infinitely long, infinitely detailed real number.
Therefore, for any problem where the answer is not an integer, you need to allow a
tolerance factor, or the students will find it nearly impossible to exactly match the
computer's idea of the answer. You may find the default tolerance too large for some

Hm, I think that last line should say "if you use the colorful editor tolerance template, the default tolerance may be too large...". I think the template defaults to 5%.

the format affects the display, not the calculations.

From: lon-capa-users-bounces at mail.lon-capa.org<mailto:lon-capa-users-bounces at mail.lon-capa.org> [mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Harding, Gene L
Sent: Tuesday, January 24, 2017 8:23 AM
To: Discussion list for LON-CAPA users <lon-capa-users at mail.lon-capa.org<mailto:lon-capa-users at mail.lon-capa.org>>
Subject: Re: [LON-CAPA-users] Unordered Response Question Error

Hi Carl,

The ! was commenting out the parameter, something I tried among several permutations of syntax hoping to get something to work. The error message is the same whether it is there or commented out. I originally also had a sig figs param in it, but deleted it. I think that eliminated one error.

I have tried putting the unit= and format= in the answer and value fields, but no luck there, either.

Gene L. Harding, PE
Associate Professor of ECET
574-520-4190
Purdue University-South Bend

From: lon-capa-users-bounces at mail.lon-capa.org<mailto:lon-capa-users-bounces at mail.lon-capa.org> [mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Carl Lira
Sent: Monday, January 23, 2017 11:22 PM
To: 'Discussion list for LON-CAPA users' <lon-capa-users at mail.lon-capa.org<mailto:lon-capa-users at mail.lon-capa.org>>
Subject: Re: [LON-CAPA-users] Unordered Response Question Error

not sure of the impact of the ! in the responseparam field. I believe you should have some tolerance if you have a calculated real number, e.g.

<responseparam name="tol" type="tolerance" default="2%" description="Numerical Tolerance" />

From: lon-capa-users-bounces at mail.lon-capa.org<mailto:lon-capa-users-bounces at mail.lon-capa.org> [mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Harding, Gene L
Sent: Monday, January 23, 2017 10:00 PM
To: 'lon-capa-users at mail.lon-capa.org' <lon-capa-users at mail.lon-capa.org<mailto:lon-capa-users at mail.lon-capa.org>>
Subject: [LON-CAPA-users] Unordered Response Question Error

Hi,

I am trying to embed some unordered numericalresponse parameters inside an xml table. I modeled my xml after the example in LON-CAPA, but am having two problems with it. The first problem is an error referring to tolerance range, and the second is incompatible units. This is a screenshot:
[cid:image001.jpg at 01D276E4.733722E0]

This is the code I am using:
<startouttext />
A \$Pa dBm, \$fa-MHz RF input signal and a \$Pb dBm, \$fb-MHz LO signal are applied to a nonlinear mixer with \$Zin-Ω impedance. Complete the table of IF cross products for m,n equal 1,2.

<! Display numeric response inside a table >
<tr>
<td> m </td>  <td> n </td>  <td> |mf<sub>a</sub> ± nf<sub>b</sub>| </td>  <td> Cross Products </td>
</tr>
<tr>
<td>1</td>  <td>1</td>
<td>
<numericalresponse format="0f" unit="MHz" id="11">
<value>\$fa</value>
<value>\$fb</value>
<!responseparam name="tol" type="tolerance" default="0" description="Numerical Tolerance" />
</numericalresponse>
</td>  <td>\$f11_1 MHz \$f11_2 MHz</td>
</tr>
<tr>
<td>1</td>  <td>2</td>
</tr>
<tr>
<td>2</td>  <td>1</td>
</tr>
<tr>
<td>2</td>  <td>2</td>
</tr>
</table>

<endouttext />

Any ideas why I am getting these two errors?

Thanks for any advice you can provide.

Best regards,

Gene L. Harding, PE
Associate Professor of ECET
574-520-4190
Purdue University-South Bend

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