Annotation of loncom/html/adm/help/tex/Numerical_Response_Randomization.tex, revision 1.2
1.2 ! bowersj2 1: \label{Numerical_Response_Randomization}
1.1 bowersj2 2:
3: For LON-CAPA, one of the most important functions is the \texttt{random}
4: function. Random takes three parameters: a \emph{lower limit}, an \emph{upper
5: limit}, and an \emph{interval}. The \texttt{\&random} function returns a
6: random value between the upper and lower limit, some integer number of \emph{interval}'s
7: away from the lower limit. Thus, for example, \texttt{\&random(1,2,.2)} might
8: return 1, 1.2, 1.4, 1.6, 1.8, or 2. \texttt{\&random} uses a uniform distribution.
9: Other distributions are available in LON-CAPA, and can be found by consulting
10: the function list.
11:
12: %
13: \begin{figure}
14: \begin{lyxcode}
15: \$a~=~\&random(1.0,10.0,1.0);
16:
17: \$b~=~\&random(-10.0,~-3.0,~1.0);
18:
19: \$answer~=~\$a+\$b;
20: \end{lyxcode}
21:
22: \caption{Sample \texttt{random} Calls \label{Sample Random Calls figure}}
23: \end{figure}
24: If you put the script in ``Sample Random Calls'' into the
25: \textbf{Script} block (replacing whatever contents might be in the block
26: already), you'll get two random variables \$a and \$b. Now, in the \textbf{Text
27: Block}, put {}``What is \$a plus \$b?'', and in the \textbf{Answer} put
28: {}``\$answer'', without the quotes for either of them. (It is a good idea
29: to create a variable to hold the answer and call it \$answer, or some other
30: reasonably standard name. Do not try to compute the answer in the \textbf{Answer}
31: field itself; it will not work as you expect.) Now save the problem and \textbf{View}
32: it. You'll see a randomized problem.
33:
34: For each student, the same random number will be used each time they visit
35: the problem, but each student will get different random numbers. For any
36: but the simplest random problems, you'll want to see several random problems
37: to make sure everything is working out correctly. This is what the \textbf{Random
38: Seed\index{Random Seed}} field is for. To see another randomized version
39: of the problem you've just created, put another number into the \textbf{Random
40: Seed} field and hit \textbf{Change}. It doesn't really matter what number
41: you put into the field. But for any given \textbf{Random Seed} with the same
42: problem, you'll see the same randomized problem generated for you. (If you
43: change the \textbf{Script}, you are no longer guaranteed to get the same
44: problem.)
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