title: How to calculate population standard deviation?
body: <p>Here is what I have so far. I need to use the number from a text file.</p>
  
  <p>Calculations class:</p>
  
  <pre><code>public class Calculations {
  
      public void readFile(String fileName, double[] myArray) throws Exception {
          FileReader fr = null;
          BufferedReader br;
  
      }
  
      public double computeStandardDeviation(double[] myArray) {
          double result = 0;
  
          return result;
      }
  
  }
  </code></pre>
  
  <p>Main class:</p>
  
  <pre><code>public class Main {
      private static int NUMBERS=20;
  
      public static void main(String[] args) {
          double[] myNumbers =  new double[NUMBERS];
          Calculations calculations = new Calculations();
          try {
              calculations.readFile("numbers.txt", myNumbers);
              double stdDev = calculations.computeStandardDeviation(myNumbers);
              System.out.println("Population Std Dev = " + stdDev);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  }
  </code></pre>