单项选择题
A.方向性强 B.相干性好 C.穿透性强 D.单色性好 E.极化性高
A.Lightactivation by stimulation emanationofradiation B.Luminant amplimeter by stimulation emission of radiation C.Light activation by strong emission of radiation D.Luminant activation before strong emission of radiation E.Light amplification by stimulation emisssion of radiation
A.单纯随机抽样 B.系统抽样 C.分层抽样 D.整群抽样 E.先分层抽样再整群抽样
A.r值的大小反映了两个变量之间是否有密切的关系B.r2值的大小反映了两个变量之间呈直线关系的密切程度和方向C.r值接近于零表明两变量之间没有任何关系D.r2值接近于零表明直线回归的贡献很小E.以上说法均不准确
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