首页
登录
职称英语
A sequence is symmetrically distributed around its arithmetic mean m, and the nu
A sequence is symmetrically distributed around its arithmetic mean m, and the nu
游客
2024-01-12
57
管理
问题
A sequence is symmetrically distributed around its arithmetic mean m, and the numbers that fall in the standard deviation d count for 68% of the total numbers in the sequence. What’s the percentage of numbers that fall below m+d?
选项
A、16%
B、68%
C、50%
D、32%
E、84%
答案
E
解析
此题考查对正态分布密度函数公式的理解。正态分布曲线为钟形,关于x=α(α为均值)对称,在第二部分的知识点中讲过,曲线下面的面积其实代表的是落在某个范围内的概率。
现在m为均值,方差为d,落在方差d内的数占总数的68%,那么在图中就是由d到α+d曲线下面的面积,刚才说过曲线关于x=α对称,那么图中由d到α以及由α到α+d曲线下面的面积都是68%/2=34%。
从均值a到正无穷曲线下面的面积是50%,那么从α+d到正无穷曲线下面的面积是50%-34%=16%,那么落在小于m+d范围内的数的百分比必然是1-16%=84%。
转载请注明原文地址:http://tihaiku.com/zcyy/3354784.html
相关试题推荐
Ifeachtermofthesequence(a1,a2…,an)iseither7or77,andthesumofthe
Ofthenumbersq,r,s,andt,whichisgreatest?(1)Theaverage(arithmeticme
Theaverage(arithmeticmean)ofMconsecutiveoddintegersis10.Whatisthesma
Asapromotionalexperiment,OmegaCompanydistributedfourmillioncatalogs.In
Iftheairspacearoundcentrallylocatedairportswererestrictedtocommercial
AlthoughthehumanpopulationaroundtheforestlandinMiddlesexCountyhasincr
Acommondisabilityintestpilotsishearingimpairment,aconsequenceofsitti
Althoughthelessercornstalkboreriswidelydistributed,controlofthemisne
Donationsofimportedfoodwillbedistributedtochildreninfamine-strickenco
Theaverage(arithmeticmean)of3differentpositiveintegersisequaltothe
随机试题
Theincreaseinglobaltrademeansthatinternationalcompaniescannotaffor
Accordingtomanyanalysts,labor-managementrelationsintheUnitedStatesare
Thisconversationismainlyabout______[originaltext]W:Ihaven’tseenyoufo
Thefitnessmovementthatbeganinthelate1960sandearly1970scenteredar
当汽车通过车辆检测器环形线圈时,其电感L的变化过程为()。A.增大 B.减小
"阴胜则寒"的证候性质是()A.假热证 B.假寒证 C.虚寒证 D.
DD表示的是H2A溶液中各离子的数量关系。
患者,女,25岁。患风湿性心脏瓣膜病,不明原因持续发热1月余,体温波动在37.5
红外测温一般检测开始测温,远距离对所有被测设备进行全面扫描,宜选择彩色显示方式,
A. B. C. D.
最新回复
(
0
)