The standard deviation, range, variation coefficient, 95% confidence interval were analyzed, the average values of 3 cycles were compared with those of 5 cycles.

计算各组变异系数、标准差、极差、均数95%可信区间，比较连续3个心动周期与5个心动周期的参数测量值。

youdao

Once you know the average return, the standard deviation of each index and the correlation coefficient between each pair of indexes, the rest is math.

FORBES: Asset Allocation and the Efficient Frontier