【单选题】【消耗次数：1】
Itwasveryhotyesterday,butitis ________ today.
①
evenhotter
②
morehotter
③
muchmorehot
④
muchhot
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相关题目
【单选题】
Itwasveryhotyesterday,butitis _______today.
①
evenhotter
②
morehotter
③
muchmorehot
④
muchhot
【单选题】
Equippedwithmodernfacilities,today’slibrariesdiffergreatlyfrom______.
①
thoseofthepast
②
thepast
③
whichofthepast
④
thesepast
【单选题】
Thereissomuchwork today.Wouldyoubekindenoughtolendmeahand？
①
havingdone
②
tobedone
③
beingdone
④
willbedone
【单选题】
It was very hot yesterday, but it is ______ today.
①
even hotter
②
more hotter
③
much more hot
④
much hot
【单选题】
Three-fourths of the homework ____ today.
①
has finished
②
has been finished
③
have finished
④
have been finished
【单选题】
_____ is it_____ made Peter_____ he is today?
①
What; that; that
②
That; that; what
③
What; what; that
④
What; that; what
【单选题】
A: Are you feeling better today? B: [填空].
①
There must be something wrong
②
Just have a good rest
③
Yes, thank you, doctor. But I still dont feel good
④
Dont worry about me
随机题目
【单选题】
设<img class=jc-formula data-tex={ X }_{ 1 },{ X }_{ 2 } src=https://huaweicloudobs.ahjxjy.cn/8C5B9B7B130A1D99BF8FFE66337C1B8E.png style=vertical-align: middle;/>是随机变量，其分布函数分别为<img class=jc-formula data-tex={ F }_{ 1 }(x),{ F }_{ 2 }(x) src=https://huaweicloudobs.ahjxjy.cn/AE9E465B957D7776F2FAC2D16C41D399.png style=vertical-align: middle;/>，为使<img class=jc-formula data-tex={ F(x)=aF }_{ 1 }(x)+b{ F }_{ 2 }(x) src=https://huaweicloudobs.ahjxjy.cn/50B1F4A25CB9F1C37173D70DFA592D21.png style=vertical-align: middle;/>是某一随机变量的分布函数，在下列给定的各组数值中应取
①
<img class=jc-formula data-tex=a=\frac { 3 }{ 5 } ,b=-\frac { 2 }{ 5 } src=https://huaweicloudobs.ahjxjy.cn/E75EDBF43B35D3C326A48C10FB9DC252.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=a=\frac { 2 }{ 3 } ,b=\frac { 2 }{ 3 } src=https://huaweicloudobs.ahjxjy.cn/3933081361337122FEBD37126A831869.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=a=-\frac { 1 }{ 2 } ,b=\frac { 3 }{ 2 } src=https://huaweicloudobs.ahjxjy.cn/48B552BE50651BEFDA8239A8EEDD3607.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=a=\frac { 1 }{ 2 } ,b=\frac { 3 }{ 2 } src=https://huaweicloudobs.ahjxjy.cn/749D2105CE67E8975F58B1E394788EF8.png style=vertical-align: middle;/>
【判断题】
设X的概率密度为<img class=jc-formula data-tex=f(x)=\left\{ 4{ x }^{ 3 },01,\\ 0,\quad \quad \quad other. \right src=https://huaweicloudobs.ahjxjy.cn/9C3C63C342998DE132E9609BDC2616F7.png style=vertical-align: middle;/>，则当<img class=jc-formula data-tex=a\le0 src=https://huaweicloudobs.ahjxjy.cn/3CF3C96715AB4C8C60A29BBB5A14C43C.png style=vertical-align: middle;/>时，有P(Xa)=P(Xa).
①
正确
②
错误
【判断题】
若<img class=jc-formula data-tex=X\~ N(\mu ,{ \sigma }^{ 2 }) src=https://huaweicloudobs.ahjxjy.cn/5DF419A43CF6DDBCD06E2491DBC671FA.png style=vertical-align: middle;/>,则<img class=jc-formula data-tex=Y=\frac { X-\mu }{ \sigma } src=https://huaweicloudobs.ahjxjy.cn/9EFAC4B5CEFCC10A8A6168A06B139DC4.png style=vertical-align: middle;/>也是一随机变量，且<img class=jc-formula data-tex=Y\~ N(0,{ 1 }) src=https://huaweicloudobs.ahjxjy.cn/56DD9D314BE46603192B5FFE9BA94EC1.png style=vertical-align: middle;/>
①
正确
②
错误
【判断题】
函数<img class=jc-formula data-tex=F(x)=\frac { x^{ 2 } }{ 1+x^{ 2 } } (-\infty \infty) src=https://huaweicloudobs.ahjxjy.cn/367C5F82E6E1F35E1BB9C3F192F1E65C.png style=vertical-align: middle;/>一定是某一随机变量X的分布函数。
①
正确
②
错误
【单选题】
设<img class=jc-formula data-tex={ F }_{ 1 }(x) src=https://huaweicloudobs.ahjxjy.cn/D8189C416F4BE785AA3C27D458B4313A.png style=vertical-align: middle;/>和<img class=jc-formula data-tex={ F }_{ 2 }(x) src=https://huaweicloudobs.ahjxjy.cn/1A4A59877F0C0C0F9978A47DC502C645.png style=vertical-align: middle;/>分别为随机变量<img class=jc-formula data-tex={ X }_{ 1 } src=https://huaweicloudobs.ahjxjy.cn/DA66F1A424E4031AEED284B5B6FE9A43.png style=vertical-align: middle;/>和<img class=jc-formula data-tex={ X }_{ 2 } src=https://huaweicloudobs.ahjxjy.cn/C81198C92D6C928414D7B3FD41B9B1FB.png style=vertical-align: middle;/>的分布函数，为使<img class=jc-formula data-tex={ F(x)=aF }_{ 1 }(x)-b{ F }_{ 2 }(x) src=https://huaweicloudobs.ahjxjy.cn/B913FD48D80BD4E167F0226DC49FAE0D.png style=vertical-align: middle;/>是某一随机变量的分布函数，在下列给定的各组值中应取
①
<img class=jc-formula data-tex=a=\frac { 3 }{ 5 } ,b=-\frac { 2 }{ 5 } src=https://huaweicloudobs.ahjxjy.cn/E75EDBF43B35D3C326A48C10FB9DC252.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=a=\frac { 2 }{ 3 } ,b=\frac { 2 }{ 3 } src=https://huaweicloudobs.ahjxjy.cn/3933081361337122FEBD37126A831869.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=a=\frac { 1 }{ 2 } ,b=\frac { 3 }{ 2 } src=https://huaweicloudobs.ahjxjy.cn/749D2105CE67E8975F58B1E394788EF8.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=a=\frac { 1 }{ 2 } ,b=-\frac { 1 }{ 2 } src=https://huaweicloudobs.ahjxjy.cn/B2C0B2D866E7A72DF28582691B6E71E0.png style=vertical-align: middle;/>
【单选题】
设随机变量X的分布函数为<img class=jc-formula data-tex={ F }_{ X }(x) src=https://huaweicloudobs.ahjxjy.cn/C9AA53C55E70D9C9A10EC19860616D92.png style=vertical-align: middle;/>，则Y=3-5X的分布函数为<img class=jc-formula data-tex={ F }_{ Y }(y) src=https://huaweicloudobs.ahjxjy.cn/C6606AD65DF04F9951D7032A6FAC7119.png style=vertical-align: middle;/>=
①
<img class=jc-formula data-tex={ F }_{ X }(5y-3) src=https://huaweicloudobs.ahjxjy.cn/AE4AC4605E1695616F4C9F45FB2D964F.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=5{ F }_{ X }(y)-3 src=https://huaweicloudobs.ahjxjy.cn/716A197607430372E288CE95DF98C9E7.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex={ F }_{ X }(\frac { y+3 }{ 5 } ) src=https://huaweicloudobs.ahjxjy.cn/43D011CA26A865C7F09E3CAD2C4C1025.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=1-{ F }_{ X }(\frac { 3-y }{ 5 } ) src=https://huaweicloudobs.ahjxjy.cn/645270C44359FC04B262389FD61E94A3.png style=vertical-align: middle;/>
【单选题】
已知随机变量X的密度函数<img class=jc-formula data-tex=f(x)=\begin{ cases } A{ e }^{ -x },x\ge \lambda \\ 0,\quad x\lambda \end{ cases }(\lambda 0,A src=https://huaweicloudobs.ahjxjy.cn/170AA0E56CF07A9CB01C1277AD5B5B64.png style=vertical-align: middle; width: 138px; height: 38px; width=138 height=38/>为常数)，则概率<img class=jc-formula data-tex=P\left\{ \lambda \lambda +a \right\} (a0) src=https://huaweicloudobs.ahjxjy.cn/414D170A5B5901D4BDB55E9237201D47.png style=vertical-align: middle; width: 142px; height: 22px; width=142 height=22/>的值
①
与a无关，随<img class=jc-formula data-tex=\lambda src=https://huaweicloudobs.ahjxjy.cn/14C3B57DF5E84C1472D22AC460DC2BA0.png style=vertical-align: middle;/>的增大而增大
②
与a无关，随<img class=jc-formula data-tex=\lambda src=https://huaweicloudobs.ahjxjy.cn/14C3B57DF5E84C1472D22AC460DC2BA0.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>的增大而减小
③
与<img class=jc-formula data-tex=\lambda src=https://huaweicloudobs.ahjxjy.cn/14C3B57DF5E84C1472D22AC460DC2BA0.png style=font-family: 宋体; font-size: 14px; white-space: normal; vertical-align: middle;/>无关，随a的增大而增大
④
与<img class=jc-formula data-tex=\lambda src=https://huaweicloudobs.ahjxjy.cn/14C3B57DF5E84C1472D22AC460DC2BA0.png style=white-space: normal; font-family: 宋体; font-size: 14px; vertical-align: middle;/>无关，随a的增大而减小
【单选题】
设随机变量<img class=jc-formula data-tex=\Chi \sim N(0，,1) src=https://huaweicloudobs.ahjxjy.cn/DFE0A2227AA81DF0DE5932390507D429.png style=vertical-align: middle;/>,X的分布函数为<img class=jc-formula data-tex=\phi (x) src=https://huaweicloudobs.ahjxjy.cn/5018A48A97FBDEAFED5147C5150F70A3.png style=vertical-align: middle;/>，则<img class=jc-formula data-tex=P(\left| X \right| 2) src=https://huaweicloudobs.ahjxjy.cn/84EB141D9A30B7BA9B748F0CE43B31F5.png style=vertical-align: middle;/>的值为
①
<img class=jc-formula data-tex=2\left[ 1-\phi (2) \right] src=https://huaweicloudobs.ahjxjy.cn/1790E87889194815A84890F2C24D912F.png style=vertical-align: middle;/>
②
<img class=jc-formula data-tex=2\phi (2)-1 src=https://huaweicloudobs.ahjxjy.cn/66E3AD4ED7467EC148F90DDAF6123574.png style=vertical-align: middle;/>
③
<img class=jc-formula data-tex=2-\phi (2) src=https://huaweicloudobs.ahjxjy.cn/DABEE0F4766062E9EC14E2FA3FE29809.png style=vertical-align: middle;/>
④
<img class=jc-formula data-tex=1-2\phi (2) src=https://huaweicloudobs.ahjxjy.cn/AE385B5AFD69AB78DD3A867D56396753.png style=vertical-align: middle;/>