组平均值 meaning in Chinese

class mean

Application of statistical . estimation of the difference of two means known variances
统计学应用.两组平均值的差的计算未知方差
Application of statistical . estimation of the difference of two means unknown but equal variances
统计学应用.组平均值的差的计算已知方差
Application of statistical . comparison of the difference of two means with a given value know variances
统计学应用.给定值与两组平均值差的比较已知方差
Application of statistical . comparison of the difference of two means with a given value unknown but equal variances
统计学应用.给定值与两组平均值差的比较相等的未知方差