A.變量x的標(biāo)準(zhǔn)差
B.變量y的標(biāo)準(zhǔn)差
C.變量x和y兩個標(biāo)準(zhǔn)差的乘積
D.變量x和y的協(xié)方差
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A.平均差大于標(biāo)準(zhǔn)差
B.平均差小于標(biāo)準(zhǔn)差
C.平均差等于標(biāo)準(zhǔn)差
D.二者關(guān)系不定
A.左偏分布
B.右偏分布
C.對稱分布
D.均勻分布
A.0
B.1
C.-1
D.0.5
A.眾數(shù)
B.中位數(shù)
C.極值
D.均值
A.簡單算術(shù)平均數(shù)
B.加權(quán)算術(shù)平均數(shù)
C.簡單調(diào)和平均數(shù)
D.加權(quán)調(diào)和平均數(shù)
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Simon Arnett, Director of Human Resources, is exploring the causes of employee absenteeism at Buderim Bottling during the last operating year (1 January 2005 to 31 December 2005). Personnel records of 50 employees are selected for analysis. (The plant employs 250.) For this study, the average number days absent for these 50 employees is a （）.
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