code: public static MutableDoubleTuple standardDeviationFromMean(
          Collection<? extends DoubleTuple> tuples, DoubleTuple mean,
          MutableDoubleTuple result)
      {
          if (tuples.isEmpty())
          {
              return null;
          }
          result = variance(tuples, mean, result);
          return DoubleTuples.standardDeviationFromVariance(result, result);
      }
docs: Returns the component-wise standard deviation of the given collection
  of {@link DoubleTuple} objects.
  The method will compute {@link #variance}, and then compute
  the actual result with the
  {@link DoubleTuples#standardDeviationFromVariance}
  method.
  
  @param tuples The input tuples
  @param mean The mean, which may have been computed before with
  {@link #arithmeticMean}
  @param result The result tuple
  @return The result, or <code>null</code> if the given collection is empty
  @throws IllegalArgumentException If the given result is not
  <code>null</code>, and has a {@link Tuple#getSize() size}
  that is different from that of the input tuples.