作者h29479341 (FLY)
看板Statistics
标题[问题] 几题选择题 不太懂
时间Sat Feb 4 22:41:50 2012
如果是跟统计软体有关请重发文章
如果跟论文有关也烦请您重发文章
文章类别是为了帮助大家搜寻资料与解答，造成不便之处请见谅
1.Let X and Y are two independent ramdom variables. Which of the following is
FALSE?
a)If X-Y and X+Y are uncorrelated then Var(X)= Var(Y).
b)If Var(X)=Var(Y) then X-Y and X+Y are uncorrelated.
c)Cov(X,XY)=Var(X)E(Y)
d) None of the above
2.If X and Y are independent standard normal ramdom variables, which of the
following is also independent?
a)X+Y and X-2Y
b)2X+Y and X-2Y
c)X+Y and 2X-Y
d)X+Y and e^x
3.X.Y are random variables X mean 65 variance 10, Y mean 65 variance 15 and
cov(X,Y)=-5
compute an upper bound p(X-Y<-15)
a)0.0625
b)0.06664
c)0.1328
d)None of the above
烦麻请大家跟我说 原因 感谢
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 59.112.83.123