天天今天给分享决定系数r2的知识，其中也会对决定系数R2是什么进行解释，希望能解决你的问题，请看下面的文章阅读吧！

决定系数r2 决定系数R2是什么决定系数r2 决定系数R2是什么


决定系数r2 决定系数R2是什么


1、SSE+SSR=SST RSS+ESS=TSSThe R-Squared ls you how much your ability to predict is improved by using the regression line, compared with not using it.The assumption is that if you don't use your regression line, you'll ignore what X is and use the mean of your Y values as your prediction.The least sible improvement is 0. This is if the regression line is no at all. You might as well use the mean of the Y values for your prediction.That is why the R-squared is always between 0 and 1. The regression line is nr worse than worthless (0), and it can't be better than perfect (1).All this is based on the assumptions behind using least squares being true. If those assumptions are not true, then it is sible that using the regression line to predict could be worse than worthless.The formula for the R-squared, and the assumptions behind using least squares regression, are in the course booklet.If your regression results show an R-squared of less than 0 or greater than 1, then one of these is true:1、There is a calculation error, or2、Your results are reporting an "adjusted" R-squared. (The template you he constructed does not do this, but some commercial statistical software does report an adjusted R-squared.) An "adjusted" R-squared tries to allow for the fact that an X variable that is really compley unrelated to your Y variable will probably he some relationship to Y in 2、商业软件展现的可能是调整后R方。

2、your data just by luck. The adjusted R-squared reduces the R-squared by how much fit would probably happen just by luck. Sometimes this reduction is more than the calculated R-squared, so you wind up with a negative adjusted R-squared.以上内容见参考资料大致说来是两种情况：1、计算错误你的情况应该就是第二种了，可以好好看看第二种情况的解释。

3、有问题Hi我。

本文到这结束，希望上面文章对大家有所帮助。