见面课：常见的假设检验及区间估计（双总体及多总体）
1、 One rule that must always be followed in constructing frequency distributions is that __.
A:adjacent classes must not overlap
B:the midpoint of each class must be a whole number
C:the width of each class is equal to the range
D:the number of intervals must be an odd number
答案: adjacent classes must not overlap
2、...