All Forums  Origin中文论坛  Origin 中文论坛 (Chinese Origin Forum)  为什么拟合后我的R^2值是负数？

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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Anti-Spam Code: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by Linda_zeng[/i] [br]R^2 = 1 - RSS/TSS RSS = Sum (wi*(y-yi)^2) // 拟合数据与原数据的平方差和 (加权重） TSS = Sum(yi-yavg)^2 // 原数据和平均值的的平方差和 当数据点少，而且数据不符合拟合模型趋势的时候，RSS>TSS=》 RSS/TSS>1=》R^2<0 所以当你看到R^2是负值的时候不要觉得软件出了bug，一个数的平方怎么会是负数呢。 [img]http://www.originlab.com/ftp/forum_and_kbase/Images/tiebaGG4.jpg[/img] [/quote]   Check here to include your profile signature.