首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The standard deviation of n numbers x1, x2, x3, …, xn with mean is equal to , where S is the sum of the squared differences (x1
The standard deviation of n numbers x1, x2, x3, …, xn with mean is equal to , where S is the sum of the squared differences (x1
admin
2019-05-11
72
问题
The standard deviation of n numbers x
1
, x
2
, x
3
, …, xn with mean
is equal to
, where S is the sum of the squared differences (x
1
-
)
2
for 1≤i≤n. If the standard deviation of the 4 numbers 5-a, 5, 25, and 25+a is 50, where a>0, what is the value of a?
选项
答案
60
解析
通过观察发现5-a,5,25,25+a这四个数是“对称”的,平均值是15,则根据标准差公式:
200+2(a+10)
2
=10000
(a+10)
2
=4900
a+10=70或-70(舍去)
a=60
转载请注明原文地址:https://kaotiyun.com/show/yckO777K
本试题收录于:
GRE QUANTITATIVE题库GRE分类
0
GRE QUANTITATIVE
GRE
相关试题推荐
Canyou______thedifference______thetwophrases?
Lifeasawomaninthecolonial(殖民的)Americaseemsquitedifferentfromitistoday.Womenwereconsideredinferiortomen,afac
Lifeasawomaninthecolonial(殖民的)Americaseemsquitedifferentfromitistoday.Womenwereconsideredinferiortomen,afac
Themaincauseofpollutionis______.Whichofthefollowingcannothelpsolvingtheproblemofpollution?
WhatarethedifferencesbetweenpublicandprivateinAmericanhighereducation?Abigdifferenceinvolvesmoney.Publiccolleg
Inarightisoscelestriangle,thelengthsofthetwononhypotenusesidesaredesignateda.Whatistheareaofthetrianglein
Ifxisapositivenumberand1/2thesquarerootofxisthecuberootofx,thenx=
IntriangleABCabove,if∠BADand∠ADBhavemeasuresof4n,∠ACBhasameasureofn,and∠DBChasameasureof45°,whatisthe
Ifthelengthsofthelegsofarighttriangleareintegers,whatistheareaofthetriangularregion?(1)Thelengthofonele
在一个有n个数的序列中,数15比序列的median少了1.5个deviation,数22比median多了2个deviation,求这个序列的median。
随机试题
对于同一根直管,不管是垂直或水平安装,克服阻力损失的能量相同。
FormonthsGinaCruz,aManilagrandmother,playedPepsiCola’s"NumbersFever"promotionlottery,buyingseveralbottlesaday
A.警告B.给予纪律处分C.责令限期整顿D.吊销执业证书E.责令改正医务人员发生医疗事故,情节严重,尚不够刑事处罚的,卫生行政部门可以给予的行政处罚是()
多为风痰上扰的病变是( )。多为热扰心神的病变是( )。
预付货款不多的企业可以不设“预付账款”账户,而是并入“应付账款”账户核算。()
党的思想建设的根本任务是()。
A、 B、 C、 D、 A观察平面图可知,B项,正面对角线应与右侧面的斜线有一个公共交点,错误。C项,上表面的斜线所在面应当与右侧面的阴影边相接触,错误。D项,当上表面是对角线时,正面的阴影方向错误。正确答案
根据以下资料,回答下列问题。如果城乡男女性别比一致,2009年,全国农村男性人口大约为()万人。
省林业厅就调整某省级自然保护区功能区一事向省人民政府发文请示,省人民政府对此文进行回复,应使用的文种是:
下列关于压力测试和负载测试说法正确的是______。
最新回复
(
0
)