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【简答题】
北京地铁是仅次于上海地铁的世界第二长的地铁。
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皮皮学刷刷变学霸
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【简答题】设 是两组样本观测值,且有如下关系: 试求样本均值 间的关系。
【简答题】冷弯检验是：按规定的________和________进行弯曲后，检查试件弯曲处外面及侧面不发生断裂、裂缝或起层，即认为冷弯性能合格。[填空(1)] [填空(2)]
【单选题】下列不属闪光对焊接头正式施焊条件的是（）
A.
每批钢筋焊接前，应先选定焊接工艺和参数，按实际条件进行试焊，并检验接头外观质量及规定的力学性能。仅在试焊质量合格和焊接工艺（参数）确定后，方可成批焊接
B.
每个焊工均应在每班工作开始时，先按实际条件试焊2个对焊接头试件，并作冷弯试验，待其结果合格后，方可正式施焊
C.
焊工具有不少50000个接头作业经验，方可正式进行实体工程施焊作业
【单选题】听力原文：M: I bought a few books at the new bookstore. Would you like to have a look at them? W: A few? It looks like you bought out the bookstore. Q: What does the woman mean? (8)
A.
She didn't like the books the man bought.
B.
There wasn't a large selection at the bookstore.
C.
The man bought a lot of books.
D.
She wanted to see what the man bought.
【单选题】设抽样得到10个样本观测值如下：19.1 20.0 21.2 18.8 19.6 20.5 22.0 21.6 19.4 20.3,则样本方差为___________.
A.
1.165
B.
1.142
C.
1.213
D.
1.152
【单选题】Directions: The following passage is about Bus tours in New York and it is followed by five statements. Read the passage, and decide whether the statements are true or false. Without a doubt, New York...
A.
True.
B.
False.
【简答题】In recent years, there has been a sharp growth in the number of tour operators who offer tours led by expert guides, and such holidays are often enhanced by special access to private collections, or a...
【单选题】设抽样得到10个样本观测值如下：19.1 20.0 21.2 18.8 19.6 20.5 22.0 21.6 19.4 20.3,则样本均值为___________.
A.
20.25
B.
20.0
C.
19.85
D.
19.68
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