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【单选题】
A problem that plagues panel studies specifically is:A.
time series.
B.
selection bias.
C.
panel mortality.
D.
panel covariance.
E.
none of these choices are correct.
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【简答题】压缩空气初步净化过程气源装置包括 、 、 、 。
【单选题】Mary is ill today. If she _____ , she ____ absent from school. A. were not ill , wouldn't be B. had been ill , wouldn't have been C. had been ill , should have been D. hadn't been ill , could be
A.
were not ill ， wouldn't be
B.
had been ill ， wouldn't have been
C.
had been ill ， should have been
D.
hadn't been ill ， could be
【简答题】a) Shaun says that "lying" and "shooting" is not a causal relationship. Which apporach he has used to make his argument? b) Please apply the notions we learned in thie context. In this story, what do ...
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