This change adds the possibility to provide randomized substitution values to short text questions via value sets.
Value sets are a means for a content developer to provide multiple matching answers which are inserted into the text before an exercise is shown to the end user. One can e.g. provide for a calculation exercise several input and some output values, such that the students get different calculation exercises provided. These values can also be used for the correct-when clauses.
The content developer can use percent-code delimited elements when defining the exercise:
--- Assume, you want to download a %x.what% with the size of %x.size% over a %x.type% connection with a rate of %x.rate% from %univ%. --- and also in "correct when" --- %x.secs% ---
the value sets can be provided via an extra field for the short-text questions and have the form of a Tcl dict:
In this example, every student will get a randomly chosen value for the university (%univ%) and matching elements containing the answer (e.g. download time of "270 MB" over "80 Mbit/s" is 27 seconds). The download time is used in the correct when part, such that auto-correction can be applied.
When a student answers this exercise, the system provides random choices that are substituted in the text. For every variable ("univ", "x", ..) different random values are used for the student. Certainly, for other students, other numbers and results will be provided. Note, that this value sets can be used for numeric an non-numeric exercises.
Current limitations: - only defined for short-text questions (can be in general also for other question types) - no elaborate user interface for entering value sets (or a thorough validator) is provided.
Added two types of grading schemes (in addition to "exact") to ordering exercises: - "position": count elements as correct, when these are on the correct position - "relative": count elements as correct, if the neighboring element is correctly before the actual element The results are adjusted by the same guessing correction as in the "ggw" scheme for MC exercises.
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