s2rout2.m

Industrial Mathematics

% Routine 2.2 
N = 10000;               % set the number of trials
m = 0;                   % initialize mean failure time
m2 = 0;                  % initialize the second moment
for i = 1:N              % begin trials
   x = 11 + randn;       % fail time for component \# 1
  y = 12 + 2*randn;      % fail time for component \# 2 
   z = 13 + 3*randn;     % fail time for component \# 3
w = min([x,y,z]);        % min fail time of \# 1, \$ 2, and \# 3
   m = m + w/N;          % add this trial to mean fail time
  m2 = m2 + w*w/N;       % add this trial to second moment
  end;                   % end of each trial
m                        % display the MTBF 
sd = sqrt(m2 - m*m)      % compute the standard deviation