常用的描述数据分布集中趋势的( )表示数据的相对离散波动程度。
A．中位数B．标准偏差C．极差D．变异系数
参考答案：D
根据对话或短文情景完成句子。
A: Hello, Sam?
B: Maria? Hi! 1.________________?
A: I'm in Mexico! I'm calling to say happy birthday!
B: Oh, thanks!
A:So, 2.________________?
B: Great! How's it going with you?
A: Pretty good. 3.________________?
B: I'm having a party. My whole family is here.
A:Oh, that sounds like fun. 4.________________?
B: Terrible. It's cold and raining.
A: How is the weather there?
B: 5.________________
A :Sounds good…
B: Uh-huh.
A: So, what are you doing in Mexico?
B: I'm visiting my grandmother…
活生产用水量应按最大小时流量计算，消防用水量应按（）计算。
