#include <cassert>
#include <cmath>
#include <vector>

//From http://www.richelbilderbeek.nl/CppMeanAndStdDev.htm
void MeanAndStdDev(
  const std::vector<double>& myVector, 
  double& mean, 
  double& stdDev)
{
  const int size = static_cast<int>(myVector.size());
  assert(size>1);
  const double dSize = static_cast<double>(size);
  mean = 0.0;
  double sumX = 0.0;
  double sumXsquared = 0.0;
  for (int i=0; i!=size; ++i)
  {
    const double value = myVector[i];
    sumX+=value;
    sumXsquared+=(value*value);
    mean+=value;
  }

  mean/=dSize;
  stdDev = std::sqrt(((dSize*sumXsquared)-(sumX*sumX))/(dSize *(dSize-1.0)));
}