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【单选题】
从均值为200,标准差为50的总体中抽取容量为100的简单随机样本,用样本均值估计总体均值。样本均值的数学期望是( )A.
150
B.
200
C.
100
D.
250
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皮皮学刷刷变学霸
举一反三
【单选题】The head of the shop came ___ to see ___.
A.
up; what was the matter
B.
up; what the matter was
C.
along; what’s the matter
D.
down; what the matter was
【单选题】The policeman came up to see_____.
A.
what the matter is
B.
what the matter was
C.
what was the matter
D.
what is the matter
【单选题】What was he doing ______ his father _______ back?
A.
while; came
B.
when; came
C.
when; was coming
【简答题】What happened to the carwhen the man came back? wasbadly damaged．
【简答题】What did children come to her for? Children came to her for ______.
【单选题】The shop owner came up to see______.
A.
what was happened
B.
what was going on
C.
what the matter was
D.
what is the matter
【简答题】What was Dr．Eric before he came to India?
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