统计推断的主要内容为()
A.统计描述与统计图表
B.参数估计和假设检验
C.区间估计和点估计
D.统计预测与统计控制
E.参数估计与统计预测
参考答案:B
I have many friends, _____ some are businessmen. [ ]
A. of them
B. from which
C. from that
D. of whom
水准测量中,转点的作用是传递高程,在同一转点上,既有本站前视读数,又有()读数。