title: Fill matrix with loop
body: <p>I am trying to create a matrix <code>n</code> by <code>k</code> with <code>k</code> mvn covariates using a loop.
  Quite simple but not working so far...  Here is my code:</p>
  
  <pre><code>n=1000
  k=5
  p=100
  mu=0
  sigma=1
  x=matrix(data=NA, nrow=n, ncol=k)
  
  
  for (i in 1:k){
          x [[i]]= mvrnorm(n,mu,sigma)
         }
  </code></pre>
  
  <p>What's missing?</p>