title: How to make training and testing set from a dataset?
body: <p>What's the best method:</p>
  
  <ol>
  <li>splitting my data into training and testing sets by making 70% of the data as training and 30% test, or</li>
  <li>using similar data for training and testing set.</li>
  </ol>
  
  <p>A- Is the second method correct and what's its disadvantages?</p>
  
  <p>B- My dataset contains 3 attributes and 1000 objects, is this good for selecting the training and testing sets from this dataset?</p>