[LON-CAPA-users] Re: Bubble sheets
Lars Jensen
lon-capa-users@mail.lon-capa.org
Thu, 05 Feb 2009 23:24:57 -0800
Hi Stuart,
Thanks for clarifying this. All we have on our scantron form is the
student-ID (the same lon-capa's "Student/Employee ID"), an optional
code, and then the question responses (A to E). The scanner report file
has this form:
Student-ID Code Responses
000135792 468 CADEAABCEDBCADEAABCEDB
tmccphys:TMCC Physics w/CODE:number:11:3:1:9:15:1: :letter
I am not aware of a paper-ID and there's no first- or last name on the form.
Would the above entry be correct for the scantronformat.tab file, or
should are the last fields required, like this
tmccphys:TMCC Physics w/CODE:number:11:3:1:9:15:1: :letter::::::
or should it be like this:
tmccphys:TMCC Physics w/CODE:number:11:3:1:9:15:1: :letter:0:0:0:0:0:0
Thanks,
Lars.
Stuart Raeburn wrote:
> Lars,
>
>> (a) What is the CODE used for?
>
> CODE is used in "anonymous" bubble sheet quizzes/exams in which each
> student receives a quiz/exam with a code (e.g., six letters: each letter
> one of A through J) in place of the student's name. This makes it
> easier to administer the quiz/exam, as it is no longer necessary to
> match a correct (named) printed quiz/exam to the corresponding student.
> Instead the students must bubble in the six character code in the
> appropriate location on the bubble sheet, so that LON-CAPA will grade
> the student's bubbled submissions according to the version of the exam
> the student answered (the CODE is used in the randomization when the
> quizzes/exams are printed). When using CODEs it is not necessry to
> print an individual quiz/exam for each student. If you decided to use
> say ten CODES you could print ten quizzes/exams (one for each of the
> CODEs) and could then photocopy each version how ever many times you
> needed to generate the required total number of quizzes/exams. To use
> anonymous quizzes/exams with CODEs your bubble sheet scanning mechanism
> needs to be able to extract the code (which the student bubbles in on a
> specific location on the bubble sheet) and include it in the raw data
> record written for each student in the columns specified according to:
> CODEstart and CODElength
>
>> (b) What is Qlength The examples uses a value of either 1 or 10. What
>> does this mean?
>
> Qlength is the number of characters in the raw data used to record the
> student's bubbled answer for each row on the bubble sheet. If the raw
> data indicate bubble position by a letter or a number (e.g., A = first
> bubble or 1 = first bubble etc.) then the number of characters would be
> 1 (assuming 10 bubbles or less for the number case). If however, bubble
> position is indicated by position of the Qon (bubbled) character, then
> each bubble row might have 10 characters (one for each of the 10
> possible positions with Qon at the position bubbled and Qoff elsewhere,
> (e.g. if Qon = 1, Qoff = . the portion of a student's record for a
> single bubble row might be: ...1...... indicating position 4 was the
> one bubbled.
>
>> (c) What is Qon and Qoff? Qoff seems to be empty in the examples. Is
>> Qon designed to explain to lon-capa any discrepancy between the
>> labeling of lon-capa question options and those on the scantron form?
>
> Qon is the character used in the raw data generated by the bubble sheet
> scanner to indicate a filled-in bubble. This could be the corresponding
> letter (A - J), or number (1,2 ... 9,0) to indicate which bubble was
> filled, or in the positional case might be a character (e.g., 1) to
> indicate the presence of a filled bubble. Qoff is the character used to
> indicate an unfilled bubble, this is commonly a single blank space.
>
>> (d) What are PaperID and PaperIDlength
> PaperID is an identifier which the bubble sheet scanner generates for
> each sheet scanned (some hardware prints this on the bubble sheet when
> scanning it so that you can match the raw data to the corresponding
> paper, in case there is a question over multiple bubbles or undetected
> bubbles on a single bubble sheet row). The PaperID is included in the
> raw bubble sheet data at the column position defined by PaperID.
> PaperIDlength is the number of characters used for this identifier.
> LON-CAPA reports the PaperID (if defined) where a bubble error is
> encountered (double bubble, missing bubble etc.) ans also uses the
> PaperID in cases where each CODE is only to be used once, i.e., each
> student receives a unique quiz/exam.
>
> For completeness, below is the text included in the bubble sheet config
> comments in /home/httpd/lib/perl/Apache/grades.pm (the LON-CAPA module
> used for grading using bubble sheet raw data files):
>
> name - internal name for the this configuration setup
> description - text to display to operator that describes this config
> CODElocation - if 0 or the string 'none'
> - no CODE exists for this config
> if -1 || the string 'letter'
> - a CODE exists for this config and is
> a string of letters
> Unsupported value (but planned for future support)
> if a positive integer
> - The CODE exists as the first n items from
> the question section of the form
> if the string 'number'
> - The CODE exists for this config and is
> a string of numbers
> CODEstart - (only matter if a CODE exists) column in the line where
> the CODE starts
> CODElength - length of the CODE
> IDstart - column where the student ID number starts
> IDlength - length of the student ID info
> Qstart - column where the information from the bubbled
> 'questions' start
> Qlength - number of columns comprising a single bubble line from
> the sheet. (usually either 1 or 10)
> Qon - either a single character representing the character
> used
> to signal a bubble was chosen in the positional
> setup, or
> the string 'letter' if the letter of the chosen
> bubble is
> in the final, or 'number' if a number representing the
> chosen bubble is in the file (1->A 0->J)
> Qoff - the character used to represent that a bubble was
> left blank
> PaperID - if the scanning process generates a unique number
> for each
> sheet scanned the column that this ID number starts in
> PaperIDlength - number of columns that comprise the unique ID number
> for the sheet of paper
> FirstName - column that the first name starts in
> FirstNameLength - number of columns that the first name spans
>
> LastName - column that the last name starts in
> LastNameLength - number of columns that the last name spans
>
> There is also some discussion of bubble sheet exams in the Course
> Coordination Manual (section 19: Scantron Examms - page 65).
>
> Stuart Raeburn
> MSU LON-CAPA group
>
>
>> Thanks Stuart and Ray for answering these questions. I still hae a
>> couple of questions on the fields in scantron.tab:
>>
>> (a) What is the CODE used for?
>>
>> (b) What is Qlength The examples uses a value of either 1 or 10. What
>> does this mean?
>>
>> (c) What is Qon and Qoff? Qoff seems to be empty in the examples. Is
>> Qon designed to explain to lon-capa any discrepancy between the
>> labeling of lon-capa question options and those on the scantron form?
>>
>> (d) What are PaperID and PaperIDlength
>>
>> Thanks so much for your help.
>>
>> Lars.
>
>
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