private double ComputeEI(double bestVal, double[] forestStatistics) { double empMean = forestStatistics[0]; double empStdDev = forestStatistics[1]; double centered = empMean - bestVal; double ztrans = centered / empStdDev; return(centered * SweeperProbabilityUtils.StdNormalCdf(ztrans) + empStdDev * SweeperProbabilityUtils.StdNormalPdf(ztrans)); }