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问题 单项选择题

标准误是指

A．所有个体值对均数的离散程度

B．某一样本均数对总体均数的离散程度

C．所有样本均数对总体均数的离散程度

D．某些样本对总体均数的离散程度

E．某个观察值对总体均数离散程度

答案

参考答案：C

单项选择题

Mobile computers-which (71) laptops, notebooks, subnotebooks and handhelds- (72) so ubiquitous in such a short time, no surprise to hear who say: "It will define the leading edge (73) the next five years or so." The most remarkable (74) mobile computers is the amount of data storage and memory packed (75) their tiny boxes. These devices not only handle windows easily but also run storage-hungry programs.

（74）处是（）

A.from

B.for

C.about

D.at

E.on

F.into
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听力题

根据对话内容,写出句中所缺单词

小题1:-Why did you go to Beijing last week?

-Oh, I went there on _______. I talked about a project with other companies.

小题2:-Come on. We only have 5 miles left.

-I'm _______ out and I can't go any further.

小题3:-It's dangerous. You should tell your brother not to go sailing alone.

-But he has already made up his _______ to do so.
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