title: Missing data in repeated measure model
body: <p>I am using the matlab function <a href="http://nl.mathworks.com/help/stats/fitrm.html?refresh=true" rel="nofollow">fitrm</a> to fit repeated measures model in order to investigate whether elements grouped according to Grouping1 have statistically different means for the variable measured at time t1,t2,t3,t4 (var_t1,var_t2,var_t3,var_t4).</p>
  
  <p>My data look like the ones in the table:</p>
  
  <pre><code>Grouping1   Grouping2     Gender     Age       BMI       var_t1           var_t2          var_t3        var_t4
  ______    ___________    ______    ______    ______    ____________    ____________    ____________    ____________
  
  C           B             Male       60       24.802    836             608             746             NaN         
  C           A             Male       67       19.818    242             544             460             483         
  ...       ...
  D           C             Female     65       21.631    621             468             NaN             NaN         
  </code></pre>
  
  <p>As you can see from I have some missing data for var_t3 and var_t4.
  Can I still use fitrm? </p>
  
  <p>If fit a repeated measures model, where var_t1,-var_t4 are the responses and Grouping1, Grouping2, Gender, Age and BMI are the predictor variables </p>
  
  <pre><code>Time = [1:4]';    
  rm = fitrm(table,'var_t1-var_t4 ~ Grouping1 + Grouping2 + Gender + Age + BMI','WithinDesign',Time)
  </code></pre>
  
  <p>the function doesn't return error, but I don't know if the results have any meaning...</p>