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【单选题】
设有一群人中受某病感染患病的占20%。现随机从此群人中抽取出50人,则患病人数的数学期望和方差分别为A.
25和8
B.
10和2.8
C.
25和64
D.
10和8
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举一反三
【简答题】vt. /n. 释放,排放;解释解脱 (r__)
【简答题】r____ vt. /n. 释放,排放;解释解脱
【简答题】Charles R. Drew was a medical student at Columbia University in New York. Before he graduated, he wrote an article __41___ blood bank, that is, the storing of blood. Up till then, a lot of people had ...
【简答题】民主社会主义的基本主张是,将资本主义的优点与社会主义的优点结合起来,同时克服二者的缺点,寻找一条介于资本主义和社会主义之间的 。
【单选题】Before he graduated ___ college, he belonged ___ several clubs and associations.
A.
in; to
B.
to; in
C.
from; to
D.
to; from
【简答题】Where did he graduate? He graduated from______．
【简答题】vt. / n. 释放,排放;解释解脱
【简答题】Charles R. Drew was a medical student at Columbia University in New York. Before he graduated, he wrote an article __36___ blood bank, that is, the storing of blood. Up till then, a lot of people had ...
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