function [m,A,B]=markquiz(filename)
% filename is character string representing excel file, first column=student ID, second and remaining columns=answer in characters
%ans=vector of correct answers.  The answers are in  the first line of the excel file.
%  for example m=markquiz('quiz.xls')
[A,B]=xlsread(filename);
n=size(B);
mark=zeros(n(1)-1,n(2)-1);
for i=2:n(1)
    for j=2:n(2)
    T0=cputime;
    eval(char(B(i,j)));
    mark(i,j-1)=(cputime-T0)*(t-ans(j-1))^2;
  end
end

sd=sqrt(var(mark));
mark=3-standardize(mark);
m=[A(:,1) mark sum(mark,2)];
%mark=average mark(=3)+zscore for each question, last column is total mark