If you have items with multiple correct answers you can easily code these as one single item: All alternatives a subject has marked should be combined
to a single value without spaces. The vector with correct answers will have to be coded accordingly,
of course. An example: If someone marked the first,
third and fourth answer,
you would code this as "134". See klausur.gen.corr for a helpful function to create such an
answer vector. Internally klausur checks for equality of given answers and correct values,
that is,
it will only give that person a point if the correct answer was coded as "134" as well.
Data for (Number Right) Elimination Testing
If your test is to be evaluated according to elimination testing (ET),
number right elimination testing (NRET) or number right (NR, which is actually
multiple choice) scoring,
the data has to be in a different format: In contrast to the usual MC procedure, ET items are answered
by eliminating all alternatives a subject considers wrong; in an NRET test subjects are asked to eliminate all wrong alternatives
and mark the one they consider the correct answer. That is,
for both scoring functions, you need to know for each answer alternative whether
a subject saw it as right, wrong or was not sure and left it open.
In this implementation,
these answers are to be coded as a plus sign "+" (right answer), a minus sign "-" (wrong answer) or a zero
"0" (missing). If you need to code errors (like both "right" and "wrong" have been marked),
use the asterisk "*" for these cases.
All answers to one item belong into one column. E.g.,
if you have four answer alternatives, a subject thought the second one to be the correct
answer and eliminated the rest,
you'd have to code this item as "-+--". The same is true for the vector of correct answers, of course.
Marks
The assigned marks are expected to be in a certain format as well,
as long as you don't want klausur to suggest them itself.
Just create an empty vector to start with (say your.marks <- c()) and fill it according to the scheme your.marks[<points from>:<points to>] <- <mark>.
For example: Should one get a 1.7 if in sum 27 to 30 points were achieved,
you'd assign these points as indices to the vector with
your.marks[27:30] <- "1.7" (see example section below). It is crucial to assign marks to the whole range of points that can be achieved in the test.
On the other hand, it's irrelevant wheter you assign decimal marks as in the example,
only integer values, a 15 marks scheme or whatever. The convenience
function klausur.gen.marks can assist you in creating such a valid vector.