方差为2的是( ) A.1,2,3,4,5 B.0,1,2,3,6 C.2,2,2,2,2 D.2,2,3,3,
方差为2的是()A.1,2,3,4,5B.0,1,2,3,6C.2,2,2,2,2D.2,2,3,3,3...
方差为2的是( ) A.1,2,3,4,5 B.0,1,2,3,6 C.2,2,2,2,2 D.2,2,3,3,3
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弘若山
2014-08-29
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分别计算出各个选项的方差后比较. A、 = ( 1+2+3+4+5)=3,方差s 2 = [(1-3) 2 +(2-3) 2 +(3-3) 2 +(4-3) 2 +(5-3) 2 ]=2,故正确; B、 = ( 0+1+2+3+6)=2.4,方差s 2 = [(0-2.4) 2 +(1-2.4) 2 +(2-2.4) 2 +(6-2.4) 2 +(3-2.4) 2 ]=4.24,故错误; C、 = (2+2+2+2+2)=2,方差s 2 = [(2-2) 2 +(2-2) 2 +(2-2) 2 +(2-2) 2 +(2-2) 2 ]=0,故错误; D、 = (2+2+3+3+3)=2.6,方差s 2 = [(2-2.6) 2 +(2-2.6) 2 +(3-2.6) 2 +(3-2.6) 2 +(3-2.6) 2 ]=0.24,故错误. 故选A. |
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