设随机变量X的方差存在, D(X)> 0，则以下结果正确的是
A. D(X)>D(1-X)
B. D(X) C. D(X)=D(1-X)
D(X)+D(1-X)=1
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设随机变量X~N(0, 1), Y~N(1,4), X与Y相互独立，则P(X
A. 大于0.5
B. 小于0.5
C. 等于0.5
D. 等于1
Why the author wasnot sure if he would be able to survive 150 thousand years ago?
A. Because he was chased by his prey.
Because sport was the key to survive at that time while the authour was not a sporty guy.
C. because he would now be the guy carrying the killed prey, while the others, the ones who run faster, would be the ones hunting the prey.
D. becausehe is not running as fast as he used to.
why is sport a metaphor for the meaning of life?
A. Both of them has the starting line and the ending line.
B. because the odds are against us.
C. because life has ups and downs like sport.
D. because we want to lie on grass of floor when we lose in either life or sport.
what would fans do whenthe goal is scored?
A. all the fans become like one big family, hugging each other
B. Fans would worship the athletes like God.
C. Fans wouldcollect pictures of their role models.
D. Fans would sing songs and cheer.
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