title: Imbalanced data: undersampling or oversampling?
body: <p>I have binary classification problem where one class represented 99.1% of all observations (210 000). As a strategy to deal with the imbalanced data, I choose sampling techniques. But I don't know what to do: undersampling my majority class or oversampling the less represented class. 
  If anybody have an advise?</p>
  
  <p>Thank you.</p>
  
  <p>P.s. <em>I use random forest algorithm from sklearn.</em></p>