直方图的平均值和标准差怎么算

简介：More than ten minutes later, when the thick smoke on the position slowly dispersed, the soldiers on the Wei Dayong Camp position could finally come out to take a breath. This poison gas attack caused a total of 20 people on the Wei Dayong Camp position. Seven soldiers died, and as many as 20 or 30 were injured at the same time. The rest could continue to fight.