[ExI] standard form for creating a test

[Anders Sandberg]

Just checked my algoritm. It works pretty well! It converges very 
quickly and robustly for people who reliably give the right answers when 
questions are easier than their skill level, and the sharpness allows to 
set how forgiving the system is to mistakes. Here is a matlab/octave script:

N=50; % number of skill levels
P=ones(1,N)/N; % Initialize
g=10; % Sharpness of sigmoid
while(1)
    bar(P) % Draw the probabilities of skills
    i=sum((1:N).*P) % Select a question of difficulty i
    answ=input(''); % Ask for 0,1 - incorrect or correct answer
    if (answ>0)
        P=P.*(.5+.5*tanh(g*((1:N)-i))); % Update prob after correct answers
    else
        P=P.*(1-(.5+.5*tanh(g*((1:N)-i)))); % Update after errors
    end
     P=P/sum(P); % Normalize
end

-- 
Anders Sandberg,
Future of Humanity Institute
Philosophy Faculty of Oxford University