title: MATLAB help for cell disruption modelling
body: <p>i keep getting the error "Error using -""Matrix dimensions must agree"
  for this piece of code. Can anybody help me and identify where i'm going wrong? I should be getting 8 plots of f vs d. </p>
  
  <pre><code>P=500;   
  N=1:1:8;   
  a=-0.4;  
  b=-1;  
  Kd=700;  
  d50star=(1./(10.^(Kd*(N.^a)*(P-115).^b)))
  
  w0=0.45;  
  d=0:0.1:10  
  d50N0=5;  
  if d50star &lt; 0.33;  
  w=(1-(2.3*d50star))*w0  
  else   
  w=(3.4-(5.5*d50star))*w0  
  end
  
  d50=(1-d50star)*d50N0; 
  
  f=1-(1./((1+exp((d-d50)/w))))
  </code></pre>