How to calculate/normalize Zero mean and unit variance
<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>