title: multicollinearity for one-hot encoding
body: <p>Do we always need to remove a column for one-hot encoding to prevent multicollinearity?
  In the solution here (<a href="https://www.kaggle.com/omarelgabry/titanic/a-journey-through-titanic/comments#138896" rel="nofollow noreferrer">https://www.kaggle.com/omarelgabry/titanic/a-journey-through-titanic/comments#138896</a>) it mentions</p>
  
  <blockquote>
    <p>@Kevin Chang You need to delete one column of the dummy variables to
    avoid the state of Multicollinearity. It's a state of very high
    correlations among the columns(independent variables); meaning that
    one can be predicted from the others. It is therefore, a type of
    disturbance in the data, and if present in the data the statistical
    conclusions made about the data may not be reliable.</p>
  </blockquote>
  
  <p>In the solutions here, there is not catering for multicollinearity
  <a href="https://www.kaggle.com/sharmasanthosh/allstate-claims-severity/exploratory-study-on-ml-algorithms" rel="nofollow noreferrer">https://www.kaggle.com/sharmasanthosh/allstate-claims-severity/exploratory-study-on-ml-algorithms</a></p>
  
  <p>May I know is it a must, or in what situation we ned to cater that?</p>