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【单选题】
若以舒张期血压≥12kPa(90mmHg)为高血压，调查某地1000人，记录每人是否具有高血压，最后清点结果，其中有10名高血压患者，有990名非高血压患者。按此资料A.
可计算出极差
B.
可计算出方差
C.
可计算出率的标准误
D.
可计算出样本标准差
E.
可计算出平均舒张压
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皮皮学刷刷变学霸
举一反三
【单选题】Britain, ______________many other industrialized countries, ______ experienced major changes over the past 100 years.
A.
together with; have
B.
as well as; have
C.
in common with; has
D.
instead of ; has
【单选题】How many Dalehouse restaurants are there in other countries at the moment?
A.
One.
B.
Two.
C.
Three.
【简答题】如将变压器误接到等电压的直流电源上时,由于E= ,U= ,空载电流将 ,空载损耗将 。
【单选题】Many important leaders of different countries______ in the opening ceremony of the 29th Olympics held on August 8,2008.
A.
turned up
B.
turned down
C.
turned on
D.
turned over
【单选题】用 LED 做 12V 电源指示,已知 LED 正向压降为 2.2V ,电流为 5mA 左右,则限流电阻应选 ( ) 为宜。
A.
200 Ω
B.
560 Ω
C.
1.8k Ω
D.
3.6K Ω
【单选题】This kind of fruit not only sells well on the local market, but is also _____ to many countries at the same time. [ ]
A.
exploited
B.
exported
C.
explored
D.
exploded
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