title: What's the range of random variable with randn in matlab?
body: <p>I am using matlab to plot the random variables satisfying the normal distribution. I plot the histogram as</p>
  
  <pre><code>w = 0.2;
  y = randn(1, 1000)*w;
  hist(y);
  </code></pre>
  
  <p>this shows the variables in the histogram ranges from -40 to 40, but what's that? I think since the width of the normal distribution is 0.2, I think the range of the variable should be within -1 to 1, right? So why the hist shows from -40 to 40? How do I know the actual range of the random variable? Thanks.</p>