1、单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,第二章习题锦集,希望班上的每一位小乖乖都能一天比一天好!,习题目录,随机抽样,1,频率分布表,直方图。折线图与茎叶图,2,众数,中位数,平均数与标准差,3,随机抽样,随机抽样有几种抽样方法,哪几种抽样方法?,简单随机抽样(抽签法,随机数表),系统抽样(等距抽样),分层抽样(总体有明显的层次),简单随机抽样,2,,从一批零件中抽出,40,个进行合格检查,发现有,36,个合格,则这批产品的合格率为(),A,36%B,72%,C,,,90%D,,,25%,1,,对于简单随机抽样各个体被抽的机会(),A,相等,B
2、不相等,C,,不确定,D,,与抽取的次数有关,A,C,简单随机抽样,3,50,名学生,学号从,01,50,号,采用随机数表法抽取,5,名同学参加晚上的游戏晚会。起始数为第,21,行第,15,个数开始,则被抽到的学生为(),A,,,30,号,,09,号,,06,号,,24,号,,36,号,B,,,30,号,,40,号,,44,号,,22,号,,26,号,C,,,30,号,,07,号,,04,号,,44,号,,22,号,D,,,30,号,,77,号,,40,号,,44,号,,22,号,B,简单随机抽样,4,,某中学高一有,400,人,高二,320,人,高三,280,人,若每人被抽取的可能性为,0
3、2,,从该总体中抽取一个容量为,n,的样本,则,n,等于(),A,,,200 B,,,80,C,,,64 D,,,56,A,系统抽样,当总体与样本个数较多时,简单随机抽样很难搅拌均匀,那么采用,系统抽样,。,如果抽取,n,个,则将总体分成,_,段,间距为,_,系统抽样的两个经典案例,n,系统抽样,1,从,50,名学生中选,5,名,采用系统抽样,则选取的,5,名学生的学号可能是(),A,,,1,,,2,,,3,,,4,,,5,B,,,3,,,13,,,23,,,33,,,43,C,,,2,,,11,,,20,,,29,,,38,D,,,4,,,6,,,10,,,16,,,24,B,系统抽样,2
4、从,1200,名学生中抽取,30,名,采用系统抽样,分段的间隔为(),A,,,40 B,,,30 C,,,20 D,,,12,A,3,,总体容量为,524,,采用系统抽样,当抽样间隔为多少时,不需要剔除个体(),A,,,3 B,,,4 C,,,5 D,,,6,B,分层抽样,1,,某高中总共,900,人,其中高一年级,300,人,高二年级,200,人,高三年级,400,人,采用分层抽样,抽取,45,人,那么高一,高二,高三年级各抽取多少人(),A,,,15,,,5,,,25 B,,,15,,,15,,,15,C,,,10,,,5,,,30 D,,,15,,,10,,,20,D,分层抽样,2,
5、调查某地区中小学生近视情况,已知高中生有,2400,人,初中生有,10900,人,小学生有,11000,人,从中抽取,1%,的学生进行调查,你认为应该怎样抽取样本?,高中生:,24,人,初中生:,109,人,小学生:,110,人,分层抽样,3,,某公司共有,1000,名员工,下设若干部门,现用分层抽样法,从全体员工中抽取一个容量为,80,的样本,已知策划部被抽取,4,个员工,求策划部的员工人数是多少?,50,人,分层抽样,4,,某农场分别在三块地种玉米,其中平地种,150,亩,河沟地种,30,亩,坡地种,90,亩,估产时,可按照,_,的比例从各快地中抽取。,5:1:3,5,,某工厂生产,A,
6、B,C,三种不同型号的产品,数量之比依次为,2:3:5,,现采用分层抽样,抽取一个,容量为,n,的样本,样本中,A,型号的产品有,16,件,,则此样本容量,n=_,。,80,频率分布表和频率分布直方图,1,,,某地区为了了解知识分子的年龄结构,,随机抽样,50,名,其年龄分别如下:,42,,,38,,,29,,,36,,,41,,,43,,,54,,,43,,,34,,,44,,,40,,,59,,,39,,,42,,,44,,,50,,,37,,,44,,,45,,,29,,,48,,,45,,,53,,,48,,,37,,,28,,,46,,,50,,,37,,,44,,,42,,,39,
7、51,,,52,,,62,,,47,,,59,,,46,,,45,,,67,,,53,,,49,,,65,,,47,,,54,,,63,,,57,,,43,,,46,,,58.,(1),列出样本频率分布表;,(2),画出频率分布直方图;,(3),估计年龄在,32,52,岁的知识分子所占的比例约是多少,.,(1),极差为,67-28=39,,取组距为,5,,分为,8,组,.,分 组 频数 频率,27,,,32,),3 0.06,32,,,37,),3 0.06,37,,,42,),9 0.18,42,,,47,),16 0.32,47,,,52,),7 0.14,52,,,57,),5 0.
8、10,57,,,62,),4 0.08,62,,,67,),3 0.06,合 计,50 1.00,样本频率分布表:,(,2,)样本频率分布直方图:,年龄,0.06,0.05,0.04,0.03,0.02,0.01,27 32 37 42 47 52 57 62 67,频率,组距,O,(,3,)因为,0.06+0.18+0.32+0.14=0.7,,故年龄在,32,52,岁的知识分子约占,70%.,2,,为了了解某地区高中学生的身体发育情况,抽查了该地区,100,名年龄在,17.5,18,岁的男生体重(单位:,kg,),得到频率分布直方图如下:,54.5 56.5 58.5 60.5 62.5
9、64.5 66.5 68.5 70.5 72.5,体重,/kg,频率,组距,0.03,0.05,0.07,求这,100,名学生中体重在,56.5,64.5,范围内的人数,.,40,3,,为了了解高一学生的体能情况,某校随机抽取部分学生进行一分钟跳绳次数测试,将所得数据整理后,画出了频率分布直方图,.,图中从左到右各小长方形的面积之比为,2,:,4,:,17,:,15,:,9,:,3,,第二小组的频数为,12.,(,1,)第二小组的频,率是多少?,(,2,)样本容量是多,少?,(,3,)若次数在,110,以,上(含,110,次)为达,标,试估计该校全体,高一学生的达标率约,是多少?,90 100
10、 110 120 130 140 150,次数,o,0.004,0.008,0.012,0.016,0.020,0.024,0.028,频率,/,组距,0.032,0.036,0.08,150,88%,茎叶图,1,,甲,乙两个班级各随机选出,15,名同学进行测验,成绩的茎叶图,如图,则甲班、乙班的最高成绩各是,_,。,从图中看,,_,班的平均成绩较高。,96,92,乙,6 4,8 5 7,9 4 1 6 2 5 9,8 7 5 4 2 1 7 2 5 7 8 9,7 4 4 8 1 4 4 7,6 9 2,众数,中位数,平均数及标准差,1,,一个样本数据按从小到大的顺序排列为,13,14,19
11、x,23,27,28,31,,其中位数为,22,,则,x,等于,_,。,21,2,,已知数据,a,a,b,c,d,b,c,c,,且,abcd,,则这组数据的众数为,_,,中位数,_,,,平均数为,_,。,c,众数,中位数,平均数及标准差,3,,一个样本方差为,那么,样本容量为,_,,,平均数为,_,。,4,,已知一组数据,x,1,x,2,x,n,的方差是,a,,那么另一组数据,x,1,-2,x,2,-2,x,n,-2,的方差是,_,。,10,60,a,将一组数据同时加上或减去一个数方差不变。,5,,在城市居民月均用水量样本数据的频率分布直方图中,从左至右各个小矩形的面积分别是,0.04,,,
12、0.08,,,0.15,,,0.22,,,0.25,,,0.14,,,0.06,,,0.04,,,0.02.,由此估计总体的众数,中位数,平均数是多少?,月均用水量,/t,频率,组距,0.5,0.4,0.3,0.2,0.1,0.5 1 1.5 2 2.5 3 3.5 4 4.5,O,众数:,2.5,中位数:,2.02,平均数:,2.02,6,,某工厂甲、乙两个车间包装同一种产品,在自动包装传送带上,每隔,30,秒抽一包产品,称其重量是否合格,,7,次抽查数据记录如下:,甲车间:,102,,,101,,,99,,,103,,,98,,,99,,,98,;,乙车间:,110,,,115,,,90,,,85,,,75,,,115,,,110.,试根据统计原理比较甲、乙两个车间的产品包装质量,.,甲车间的产品包装质量较稳定,.,7,,对某种新品电子元件进行寿命终极度实验,实验数据如下:,试估计总体寿命的平均数,.,30,40,80,30,20,个 数,500,600,400,500,300,400,200,300,100,200,寿命(,h,),150,0.1+250,0.15+350,0.4+450,0.2+550,0.15=365,(,h,),The end,thank you!,老师衷心希望每位同学能够日有所长!,






