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问题 多项选择题

M车间生产螺钉。为了估计螺钉的长度，从当日成品库中随机抽取25个螺钉，测量了它们的长度，样本均值为22.7mm。并且求出其长度总体均值的95%置信区间为（22.5，22.9）。下述哪些判断是不正确的（）

A.当日生产的螺钉中，有95%的螺钉之长度落入（22.5，22.9）之内。

B.当日任取一个螺钉，其长度以95%的概率落入（22.5，22.9）之内。

C.区间（22.5，22.9）覆盖总体均值的概率为95%。

D.若再次抽取25个螺钉，样本均值以95%的概率落入（22.5，22.9）之内。

答案

参考答案：A, B, D

单项选择题

Standard English is the variety of English which is usually used in print and which is normally taught in schools and to non-native speakers learning the language. It is also the variety which is normally (1) by educated people and used in news broadcasts and other (2) situations. The difference between standard and nonstandard, it should be noted, has (3) in principle to do with differences between formal and colloquial (4) ; standard English has colloquial as well as formal variants.

(5) , the standard variety of English is based on the London (6) of English that developed after the Norman Conquest resulted in the removal of the Court from Winchester to London. This dialect became the one (7) by the educated, and it was developed and promoted (8) a model, or norm, for wider and wider segments of society. It was also the (9) that was carried overseas, but not one unaffected by such export. Today, (10) English is arranged to the extent that tile grammar and vocabulary of English are (11) the same everywhere in the world where English is used; (12) among local standards is really quite minor, (13) the Singapore, South Africa, and Irish varieties are really very (14) different from one another so far as grammar and vocabulary are (15) .Indeed, Standard English is so powerful that it exerts a tremendous (16) on all local varieties, to the extent that many of long-established dialects of England have (17) much of their vigor and there is considerable pressure on them to be (18) . This latter situation is not unique (19) English: it is also true in other countries where processes of standardization are (20) .But it sometimes creates problems for speakers who try to strike some kind of compromise between local norms and national, even supranational ones.

15（）

A.talked

B.concerned

C.mentioned

D.involved
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单项选择题

生活中我们常说的"一把钥匙开一把锁"，反映的是教学中的（）原则。

A.启发性

B.因材施教

C.直观性

D.导向性
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