【单选题】Another worry is that telecommunication systems may isolate people ______ each other.
【多选题】企业按照某种标准将市场上的顾客划分成若干个顾客群,然后进行的定位属( )。
【单选题】设随机变量X和Y都服从标准正态分布,且X和Y相互独立,则( ).
C.
X 2 和 Y 2 都服从 c 2 分布 .
【单选题】设随机变量 X 和 Y 都服从标准正态分布,且 X 和 Y 相互独立,则下列选项不正确的是 ( ).
【单选题】Why do people dream what they worry about?
A.
Because the brain tries to help people prepare for the occurrence of a disaster.
B.
Because the brain tries to develop people's ability to learn to deal with a disaster.
C.
Because dreams can make people feel less worried about the occurrence of a disaster.
D.
Because dreams can help people remember what to do when a disaster occurred.
【单选题】有关尸体供肾的绝对禁忌证,下列哪项正确()
【单选题】有关尸体供肾的绝对禁忌证,下列哪项正确()
【单选题】设随机变量X和y相互独立且都服从标准正态分布N(0,1),考虑下列命题: 其中正确的个数为
【单选题】The word 'specter' in the second paragraph probably means
A.
something that people worry about.
B.
something that people know about.
C.
something that people are aware of.
D.
something that people are afraid of.