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问题 单项选择题

某样本数据在正态纸上描点，目测这些点在一直线附近，表示数据来自于正态总体，现从纵坐标轴上取概率为0.5，则其对应于近似直线上点的横坐标是正态总体( )的估计。

A．标准差σ

B．均值μ

C．μ+σ

D．μ-σ

答案

参考答案：B

解析： 正态分布的均值是其分布的中心位置，概率密度函数曲线下的面积的一半为0.5，所以在正态概率纸上概率为0.5处对应的就是均值μ的估计值。

单项选择题

People are indulging in an illusion whenever they find themselves explaining at a cocktail（鸡尾酒）party, say, that they are "in computers," or "in telecommunications," or "in electronic funds transfer". The implication is that they are part of the high-tech world. Just between us, they usually aren't. The researchers who made fundamental breakthroughs in those areas are in a high-tech business. The rest of us are(1)of their work. We use computers and other new technology components to develop our products or to organize our affairs. Because we go about this work in teams and projects and other tightly knit working groups（紧密联系在一起的工作小组），we are mostly in the human communication business. Our successes stem from good human interactions by all participants in the effort, and our failures stem from poor human interactions. 　　

The main reason we tend to focus on the(2)rather than the human side of the work is not because it's more(3), but because it's easier to do. Getting the new disk drive installed is positively trivial compared to figuring out why Horace is in a blue funk（恐惧）or why Susan is dissatisfied with the company after only a few months. Human interactions are complicated and never very crisp（干脆的，干净利落的） and clean in their effects, but they matter more than any other aspect of the work. If you find yourself concentrating on the(4)rather than the (5), you're like the vaudeville character（杂耍人物）who loses his keys on a dark street and looks for them on the adjacent street because, as he explains, "The light is better there!".

空白（2）处应选择（）

A.technical

B.classical

C.social

D.societal
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填空题

为债务人抵押担保的（），在抵押权人实现抵押权后，有权向债务人追偿。
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