题目

若一组数据 的方差是4,那么另一组数据 的标准差是（ ） A . 7 B . 2 C . 4 D . 6 答案：DJohn was one of the top students in our class, but believe it or not, he_______ passed the English exam last term.(西安市)A．easilyB．actuallyC．successfullyD．barely