/*
Calculate the running standard deviation. This means
we only need to run through the data once. Whereas other
methods require the mean of the values first, hence a previous run.
*/
double CSdDlg::CalcSD()
{

	int iSample = 0;
	double dRunningMeanSquared = 0.0;
	double dRunningTotal = 0.0;
	double dRunningTotalSquared = 0.0;
	double dSD = 0.0;
	
	for(int i = 0;i < m_dValues.GetSize();i++)
	{
		iSample++;
		double dValue = m_dValues.GetAt(i);
		
		dRunningTotalSquared += (dValue * dValue);
		
		dRunningTotal += dValue;
		dRunningMeanSquared = (dRunningTotal * dRunningTotal) / iSample;
		
		dSD = sqrt( ((1.0 / iSample) * (dRunningTotalSquared - dRunningMeanSquared)) );

		TRACE("SD = %f\n",dSD);
		
	}
	
	return dSD;
}