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【单选题】
The last sentence of Paragraph 3 means that______.A.
engaging people effectively in what they are concerned about is much more valuable than just complaining about people's ignorance of understanding science
B.
to make people take part in what they are interested in, the scientific community should beat drums hard to arouse their interest
C.
the better way to engage people in what they are concerned about is to teach them how to beat a drum
D.
none of the above
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【单选题】设随机变量 X 1 , X 2 ,..., X n ,...独立同分布,且 i=1 , 2 ..., 0 令 Φ( x )为标准正态分布函数,则
A.
0
B.
Φ（ 1 ）
C.
1 －Φ（ 1 ）
D.
1
【单选题】设随机变量X1,X2,......,Xn相互独立,且服从同一个分布,密度函数为f(x),则X1,X2,......,Xn的联合密度函数为
A.
f(x)^n
B.
f(x1)f(x2)…f(xn)
C.
f(x1)+f(x2)+…+f(xn)
D.
nf(x)