A:Having a talk with the student
B:One talk with the student
C:Given a talk with the student
D:If you have a talk with the student
读图,完成下列各题
一组数据3,6,5,2,3,4的极差是____.
已知甲、乙、丙三个车间一天内生产的产品分别是150件、130件、120件,为了掌握各车间产品质量情况,从中取出一个容量为40的样本,该用什么抽样方法?简述抽样过程.