title: How to calculate/normalize Zero mean and unit variance
body: <p>What is "Zero mean and unit variance" and how to calculate/normalize it for single column file in R? I also want to divide the normalized values into two classes:</p>
  
  <ol>
  <li>normalized value at least 0.5 standard deviation (SD) above the mean</li>
  <li>normalized value at least 0.5 standard deviation (SD) below the mean</li>
  </ol>
  
  <p>Thanks</p>