[LON-CAPA-users] correct answer changing to incorrect

[James Mueller]

Stuart,
	The student was almost certainly on an access server. Where would I look to see from which server(s) he made each of these submission?
-Jim

On Dec 8, 2010, at 4:51 PM, Stuart Raeburn wrote:

> Hi,
> 
> The timestamp of Tue Nov 30 05:10:17 am is significant here.
> 
> 5.10 am is the time LON-CAPA servers check their connections with  
> other servers in the network, and resend any critical transactions to  
> library servers which could not be completed when submission  
> originally occurred.
> 
> One possibility is that the student was logged in to a server other  
> than the library server, when the student's submission on part 11 was  
> made, and the server was unable to complete the transaction to store  
> it on the pitt.edu library server.  Given that part 11 was graded  
> correct on 11/21, if this submission occurred after that date, but  
> before the due date on 11/29, then correctness and tries information  
> must also have not been transferred from library server to session  
> server initially; hence a try was allowed and this was "Trial 1" as  
> far as the access server was concerned.
> 
> When pending transactions were re-tried the next morning the store on  
> the library server was successful. I recommend looking at the  
> submission history to see which LON-CAPA host was hosting the  
> student's session for this submission:
> 
> Tue Nov 30 05:10:17 am 2010 (EST)Part: 11 (ID 12) Trial 1  0.0490 m
> Part: 11  incorrect
> 
> Stuart Raeburn
> MSU LON-CAPA group
> 
> Quoting James Mueller <mueller@pitt.edu>:
> 
>> More details on this problem.
>> 
>> If I check grades, he does have credit for getting this one correct.  
>>  It is just that when he looks at the problem, it is displayed as   
>> incorrect answer.  The other thing I don't understand is the due   
>> date for this problem was Nov. 29, so where does this incorrect   
>> submission on Nov 30 come from?
>> 
>> -J. Mueller
>> 
>> On Dec 8, 2010, at 3:51 PM, James Mueller wrote:
>> 
>>> A student just complained that he solved a problem but later Lon   
>>> Capa said he was incorrect.  I looked at his submissions and see   
>>> the following.  From the submissions, it looks like he completed   
>>> every part of the problem on Nov 21, but on Nov 30, his first   
>>> incorrect answer for the first part appears to be entered again,   
>>> and it is listed as the first trial.  I can give him credit for   
>>> getting this correct, but does anyone have any ideas as to how this  
>>> might happen?
>>> 
>>> -Jim Mueller
>>> 
>>> Sun Nov 21 06:34:31 pm 2010 (EST)Part: 11 (ID 12) Trial not counted  0.0490
>>> Part: 11  no_unit
>>> Sun Nov 21 06:34:33 pm 2010 (EST)Part: 11 (ID 12) Trial 1  0.0490 m
>>> Part: 11  incorrect
>>> Sun Nov 21 06:35:54 pm 2010 (EST)Part: 11 (ID 12) Trial 2  2.0944 m
>>> Part: 11  approx_ans
>>> Sun Nov 21 06:38:14 pm 2010 (EST)Part: 13 (ID 14) Trial not   
>>> counted  284.8377 m/s
>>> Part: 13  sig_fail
>>> Sun Nov 21 06:38:19 pm 2010 (EST)Part: 13 (ID 14) Trial 1  284.81 m/s
>>> Part: 13  incorrect
>>> Sun Nov 21 06:38:23 pm 2010 (EST)Part: 13 (ID 14) Trial 2  284.84 m/s
>>> Part: 13  incorrect
>>> Sun Nov 21 06:39:19 pm 2010 (EST)Part: 13 (ID 14) Trial 3  45.33 m/s
>>> Part: 13  approx_ans
>>> Sun Nov 21 06:41:29 pm 2010 (EST)Part: 15 (ID 16) Trial 1  6.66 m/s
>>> Part: 15  approx_ans
>>> Tue Nov 30 05:10:17 am 2010 (EST)Part: 11 (ID 12) Trial 1  0.0490 m
>>> Part: 11  incorrect
> 
> 
> 
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