正态分布你身边的高考专家 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. . ),(),( f(x) ),0 ,, 2 2 态曲线它的密度曲线简称为正, 或的表示式可简记为)表示, , ( 的正态分布,用、为服从参数称为常数,且(????????????N N N Rx?? 2 2????????==DE N的期望与方差分布为: 则若的概率密度为: 如果随机变量? 2 22???????)x(e2 1 f(x) Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. X Y??x Rx,e)x(f )x(???????? 2 222 1),(N),(N 2????或总体平均数??标准差?????D Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. X Y ??x ;xx ).( 轴不相交轴上方,与曲线在 1; ).( 线对称曲线关于直??x2 . 曲线间高、两边低”的钟形出“中曲线不断地降低,呈现向左、向右远离时, 当曲线处于最高点, 时当 x ,x ).(??3. 轴无限的靠近轴为渐进线,向以两边无限延伸时, 并且当曲线向左、向右时,曲线下降当时,曲线上升; 当xx .x x ).(????4. 表示总体的分布越集中, 越小,曲线越“瘦高”; 表示总体的分布越分散, 越大,曲线越“矮胖”确定, 一定时,曲线的形状由当????).(5 2 222 1 ???????)x(e)x(f Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 2 222 1 ??????)x(e)x( 2 22 2 xe)x( ???? 4 1 222 1 )x(e)x( ??? 2 22 1 xe)x(??例题 () . B ..D;.C;.B;A D N~42 121 2 1 22 2. . )的值为() ( 则), , ( 设随机变量例题??C Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. . 的单调区间)求( 的最大值; )求( 是偶函数; )求证: ( )的概率密度函数是: , ( 正态总体例题)x(f )x(f )x(f e)x(f N )x(3 2 1 2
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