  <span class='kw'>X</span> <span class='kw'>=</span> <span class='no'>simulated_data</span>[ ,<span class='fu'><a href='https://www.rdocumentation.org/packages/base/topics/names'>names</a></span>(<span class='no'>simulated_data</span>) <span class='kw'>%in%</span> <span class='fu'><a href='https://www.rdocumentation.org/packages/base/topics/paste'>paste0</a></span>(<span class='st'>"covar"</span>, <span class='fl'>1</span>:<span class='fl'>6</span>)],
  <span class='kw'>GPSM</span> <span class='kw'>=</span