A N(0，3) B <img src="https://www.beizhujiaoyu.com/uploads/202208/161223453191601.png" width="27" height="30" />(3) C t(3) D F(1，1)

A 1 B -1 C 2 D -2

A A与B至少有一个发生 B 不可能事件 C A与B恰有一个发生 D A与B不同时发生

A 0．745 B 0．255 C 0．509 D 0．273

A -15 B 15 C 19 D 18

A 1-<img src="https://www.beizhujiaoyu.com/uploads/202208/1612234499321.png" width="22" height="20" />(x) B 1-<img src="https://www.beizhujiaoyu.com/uploads/202208/161223451026651.png" width="22" height="20" />(<img src="https://www.beizhujiaoyu.com/uploads/202208/161223450548401.png" width="17" height="37" />) C <img src="https://www.beizhujiaoyu.com/uploads/202208/161223451591451.png" width="22" height="20" />(x) D <img src="https://www.beizhujiaoyu.com/uploads/202208/161223452534041.png" width="22" height="20" />(<img src="https://www.beizhujiaoyu.com/uploads/202208/161223452153231.png" width="17" height="37" />)

A <img src="https://www.beizhujiaoyu.com/uploads/202208/161224078996161.png" width="29" height="52" /> B 4 C <img src="https://www.beizhujiaoyu.com/uploads/202208/161224079463231.png" width="30" height="52" /> D -<img src="https://www.beizhujiaoyu.com/uploads/202208/16122408002621.png" width="20" height="52" />

A <img src="https://www.beizhujiaoyu.com/uploads/202208/161223618687621.png" width="27" height="30" />(n-1) B <img src="https://www.beizhujiaoyu.com/uploads/202208/161223619083851.png" width="27" height="30" />(n) C t(n-1) D t(n)

A <img src="https://www.beizhujiaoyu.com/uploads/202208/161223448360141.png" width="20" height="52" /> B 4 C <img src="https://www.beizhujiaoyu.com/uploads/202208/161223449092331.png" width="27" height="52" /> D 16

A E(2X-2Y)=0 B E(2X+2Y)=4μ C D(2X-2Y)=0 D X与Y不相关