按照一定的顺序,机械地每隔一定的数量单位抽取一个单位进入样本的抽样方法称为()
A.单纯随机抽样
B.系统抽样
C.分层抽样
D.整群抽样
E.多级抽样
参考答案:B
House prices vary from place to place and are usually high _____ there are famous schools.
A.where
B.since
C.when
D.whether
随机抽样