Re: [WWdevel] webwork: problem values getting set to zero

[Michael G. <ga...@ma...>]

Ok.  so for the "value" (amount the problem is worth) variable.

Positive numeric states clearly have meaning.
the 0 state should have meaning also -- probably indicating that it is=20=

an optional problem -- certainly that it gets no credit.

What is the interpretation of the NULL state or the ""  to be?  Do we=20
have or can we imagine
  a use for states of "value" that are not numeric?

If we are always going to use it as an integer, there is no reason that=20=

we can't enforce that it is an integer.
If we are going to use other states we should try to be clear about how=20=

these states should be interpreted.

Take care,

Mike
On Jul 14, 2005, at 2:03 PM, John Jones wrote:

>  This discussion of storing the student's score refers to the=20
> student-problem field status.=A0 It was not affected by my changes to=20=

> the types of fields in mysql databases - it is still stored as type=20
> text rather than type int.=A0 (Maybe it should be stored as an int, =
but=20
> that's a different question.)
>
>  The problem Gavin discovered was with value - the number of points=20
> the problem is worth.=A0 It is one of several fields currently stored =
as=20
> type int, and they probably all will suffer the same difficulty if=20
> they are override fields for a more global value.=A0 It is a pretty=20
> serious bug, so I will attempt to fix this as soon as we know which=20
> way we want to go.
>
>  I think our options are:
> 	=95 	in all cases, when storing "" in the database, store it =
as NULL.=A0=20
> It will be promoted back when the information is retrieved.=A0 I think=20=

> this is safe.
> 	=95 	when storing back to the database, only demote "" to =
NULL if the=20
> field is of integer type.
> 	=95 	stop using integer types in the database.
>
>  John
>
>
>  Michael Gage wrote:
>>  On Jul 14, 2005, at 12:45 PM, P Gavin LaRose wrote:
>>
>>>
>>>  Isn't the distinction between "haven't tried" and "score of zero"=20=

>>> also
>>>  captured by the attempted field in problem_user?=A0 I think if the=20=

>>> status
>>>  codes this also, it's redundant information.
>>>
>>>  Am I making sense?
>>>  Gavin
>>>
>>
>>  when extracting scoring data because we were getting a lot spurious
>>  "undefined variables" warnings.=A0 We also get a=A0 lot of =
"non-numeric=20
>> in comparison" errors
>>  when sorting, etc. etc. etc.=A0 In any case I think this is why most=20=

>> things are promoted
>>  from null at least to "" or to 0.
>>
>>  In light of what you have pointed out I suggest that we "insist"=20
>> that the student score
>>  be a number.=A0 I believe that blanks are automatically converted to=20=

>> 0, so they would be ok in sorts.
>>  (I haven't checked this.)=A0 Otherwise we'll need checks in every =
sort=20
>> routine as well as other places.
>>  Use the "attempts" field to determine if the problem hasn't been=20
>> tried yet.
>>
>>  We may need to fix some assumptions in the grading and scoring=20
>> packages to conform to this.
>>  The simplification in sorts that we gain by assuming that score is=20=

>> always a number seems to
>>  me to outweigh desires for more, occasionally non-numeric states.
>>
>>  Take care,
>>
>>  Mike
>>
>>
>>> On Thu, 14 Jul 2005 at 12:39 Michael Gage wrote:
>>>
>>>> Could we get a list of what states are needed for the student =
score?
>>>>
>>>>  number=A0=A0=A0=A0 -- means the student has achieved this score on =
this=20
>>>> problem
>>>>  0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 --=A0 means the =
student has tried this problem but
>>>>  hasn't gotten in correct
>>>>  null/ blank=A0 -- means that the student hasn't tried the problem.
>>>>
>>>>  Are there are other states we need?
>>>>
>>>>  Do we need the state that distinguishes between "hasn't tried the
>>>>  problem" and the one where the score is zero?
>>>>  I think perhaps we do, so that we can warn the student they=20
>>>> haven't yet
>>>>  completed an assignment while not
>>>>  bugging them about problems that they haven't successfully=20
>>>> completed.
>>>>
>>>>  any other thoughts on what is needed?
>>>>
>>>>  Take care,
>>>>  Mike
>>>
>>>  --=A0
>>>  P. Gavin LaRose, Ph.D.=A0 Program Manager (Instructional Tech.)
>>>  Math Dept., University of Michigan
>>> gl...@um...=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0 "There's no use in trying,"=20
>>> [Alice]
>>>  734.764.6454=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0 said. "One Can't believe=20
>>> impossible
>>> http://www.math.lsa.umich.edu/~glarose/=A0 things." "I daresay you=20=

>>> haven't had
>>>  =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 much practice," said =
the=20
>>> Queen.
>>>  =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 -=20
>>> Lewis Carrol
>>>
>>
>>
>>
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