Quiz results not or badly stored sometimes

Quiz results not or badly stored sometimes

by Balázs Györök -
Number of replies: 12

Hi!

I have a serious problem. We use Moodle (1.5.2+) for our engineer students. They can get the credit if they pass all tests.

A test consist of 5 questions (cloze, calculated, multiple choice..), 2 points each.

When they submit the results, sometimes thay get an error message that the result was not stored (I could not force this error). After that what I can see as admin is that the e.g. the student has scored 2+2+2+2+2, but the final result is 0 or 2. Even if I force Moodle to regrade, the result does not change.

1. What may cause the problem?

2. What can I do to correct the already badly stored results (my main question)?

We soon close the term thus any suggestions are welcome, urgent!!

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In reply to Balázs Györök

Re: Quiz results not or badly stored sometimes

by Anthony Borrow -
Picture of Core developers Picture of Plugin developers Picture of Testers
I have found the grading of quizzes to be somewhat mysterious and frustrating. It seems that the logic is that once some type of penalty has been applied then it is recorded. For example, I have had several instances of where a quiz has timed out and recorded a grade of 0 for the student where they have 90% of the questions correctly answered. Even if I manually change the time finish so that it no longer causes a penalty and then regrade I do not get a correct grade. I think that the logic in grading needs to be looked at.  Peace - Anthony
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Re: Quiz results not or badly stored sometimes

by Balázs Györök -

I 've exported the results to Excel. I summed up the partial results compared that to what moodle had calculated. Disaster! Some 50 % had a results 10 percent higher than what should have been, whilst some 5 percent got 0 percent of their actual performance.

Their credit depends on this, they will just kill me black eye

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In reply to Anthony Borrow

Re: Quiz results not or badly stored sometimes

by Timothy Takemoto -
I have had two (of about 500) students say that they have had quizzes time out and give them a grade of 0 even though they got most of the answers right, and that the answers were displayed as right in the review window but not in their grades. I thought it was a glitch, and deleted the quiz attempt so that they could start again.
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Re: Quiz results not or badly stored sometimes

by Anthony Borrow -
Picture of Core developers Picture of Plugin developers Picture of Testers
I too have seen this and I thought it was just an issue with it timing out; however, even after increasing the percentage of time allowed significantly before it assesses the penalty it still was scoring them as zero. I even tried manually adjusting the time finished and regrading with no luck. IMO regrade needs to start from scratch by clearing whatever values were in states and/or recent states. I have not had the chance to look closely at the code but I suspect that it is in need of some attention.
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Re: Quiz results not or badly stored sometimes

by Balázs Györök -

Thank you all for your replies!

It seems that the problem has nothing to do with time limit (as I did not set any) or penalty (no penalty either). It look as a data storage problem (presumably PHP error, I am looking up the registers). I do not know the reason for the fault, but found a trick to get rid off the outcomes, which I am pleased to share:

Simple regrading had no effect. But if I changed the scores of the individual quiz questins (they were 2 each by default and changed them to 1), and then made a rescoring, the outcome was a correct summing up of the results. I assume that the problem will exist in the future (incidentally), but letting the students know the issue (and by making regular regrading) the system can be kept a useful means of testing the knowledge of our students.

One thing is sure anyway: this is a bug that needs to be corrected. I still admire the developers for the incredible work performed so far as I know complexity (knowledge) increases the appearance of such mistakes. As a freerider the only thing I may hope for is a solution smile.

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In reply to Timothy Takemoto

Re: Quiz results not or badly stored sometimes

by Timothy Takemoto -

It has happened again (please see screenshot attached). A student has all the answers correct but there grade is zero. There may be others too that the students have not themselves noticed.

I tried changing the grade and then regradign but that did not effect the issue. The score/grade for the attempt remains at zero even though all the answers are correct.

Attachment test.jpg
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In reply to Timothy Takemoto

Re: Quiz results not or badly stored sometimes

by Balázs Györök -

I have found the problem, which is in the database. Field sumgrade in table mdl_quiz_attempts is set to be varchar(10), which fails to store floatingpoint results. Change it to 20 or whatever you like, and it will start to work. Strange, but this problem could be reproduced in case of postgres only, which is possibly due to differences in the length of floatingpoint numbers.

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In reply to Balázs Györök

Re: Quiz results not or badly stored sometimes

by Dave Solon -
Has anyone tried this fix yet?

We've been having problems scoring like the others in this thread, but thought it was because we were assigning penalties.

I'll pass this along to our head-tech and see if he can fix it and then report back.

Thanks!

-Dave S.


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Re: Quiz results not or badly stored sometimes

by Dave Solon -
No luck.  Anyone have other ideas?

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Re: Quiz results not or badly stored sometimes

by Laura ***** -

I had this problem today too.  Most quizzes marked fine, but three of the eighteen showed up zero for a total score.  It threw me for a loop since this had never happened to me before.

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In reply to Balázs Györök

Re: Quiz results not or badly stored sometimes

by Konrad Lorinczi -

I still have this bug in Moodle v1.9.13.
When user clicks to one of the bottom buttons on /mod/quiz/attempt.php page,
the user is forced to login again, losing all the answers ticked.

Browser is Firefox v3.6.27, Apache2 webserver, Debian OS.
Tried to set PHP's gc_maxlifetime (in Apache config) to 4 hour (14400), but still the users are logged out after about half hour.

<Directory /domains/moodle/moodle_v1_9_13/htdocs>
    Options Indexes FollowSymLinks MultiViews
    AllowOverride None
    Order allow,deny
    allow from all

    php_value register_globals Off
    
    # Fix for Moodle quiz timeout
    php_value session.gc_maxlifetime  14400
</Directory>

Moodle's session timeout is set to 4 hour.

 
Any idea?

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