Even the total variance is small, a careful analysis is still necessary. A small total variance may be made up of large individual variances that offset each other.

• 不过,即使总差异很小,进行详细分析也很必要。因为形成总差异的各单项差异可能很大,但可能互有正负,所以相互抵消,以至总体表现数额很