一个容量为20的样本数据,分组后,组距与频数如下:(10,20],2;(20

一个容量为20的样本数据,分组后,组距与频数如下:(10,20],2;(20,30),3;(30,40),4;(40,50),5;(50,60),4;(60,70),2,则样本在(一∞,50)上的频率为    (    )

A.1/20        B.1/4    C.1/2        D7/10

答案

D

相关题目

为解决百姓看病难看病贵的问题,北京市政府继建立城镇职
为解决百姓看病难看病贵的问题,北京市政府继建立城镇职工基本医疗保险制度和新型农村合作医疗制度后,今年又建立城乡“一老一小”医疗保险制
One year our family decided to have a special celebration of Mother’s Day, as
One year our family decided to have a special celebration of Mother’s Day, as a token of appreciations for all the sacrifices that Mother had made for us. After breakfast we had arranged, as a s
(08年岳阳一中质检)用如图所示的实验装置观察光的薄膜干
(08年岳阳一中质检)用如图所示的实验装置观察光的薄膜干涉现象。图(a)是点燃的酒精灯(在灯芯上洒些盐),图(b)是竖立的附着一层肥皂液薄
 –Could you ___,please? A.     pass the cup of tea me        B.
 –Could you ___,please? A.     pass the cup of tea me        B. pass me to a cup of tea C. give me a cup of tea          D. give a cup tea to me
高铁电池是一种新型可充电电池,电解质溶液为KOH溶液,该
高铁电池是一种新型可充电电池,电解质溶液为KOH溶液,该电池能长时间保持稳定的放电电压,放电时的总反应为:3Zn+2K2FeO4+8H2O===3Zn(OH)2+2Fe(OH)3+4K
— ____busy  schoolwork,the children also have to take arts,music and sports
— ____busy  schoolwork,the children also have to take arts,music and sports classes in their free time. —I wonder what they will become.      A.Rather than              B.Owing
设函数的定义域为集合,函数 的定义域为集合。 求: ⑴,
设函数的定义域为集合,函数 的定义域为集合。 求: ⑴,;  ⑵,。 
《论语·学而》:“君子务本,本立而道生,孝弟也者,其为
《论语·学而》:“君子务本,本立而道生,孝弟也者,其为仁为本欤。”由此,可见孔子仁的学说的逻辑起点是 (    ) A.人性本善           B.

最新题目