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机器学习中使用的“相对绝对误差”和“Root相对正方差”公式(按Weka计算)
原标题:Formula for "Relative absolute error" and "Root relative squared error" used in machine learning (as computed by Weka)

在开放源码数据挖掘软件Weka(在爪哇写作)中,当我运行一些数据挖掘算法,如Linear回归Weka返回模型和测试数据的一些模型评价指标时。

看起来是这样的:

Correlation coefficient                  0.2978
Mean absolute error                     15.5995
Root mean squared error                 29.9002
Relative absolute error                 47.7508 %
Root relative squared error             72.2651 %

“相对绝对误差”和“Rooot相对正方形误差”的公式是什么?我无法理解这一点。我想用这些衡量尺度来评估我自己在Matlab的算法。

最佳回答

"http://www.liacs.nl/home/joost/DM/mod_11_eval_lift_cost.ppt" rel=“norefererr”>这个 演示文稿,在幻灯片22中,并引用Wighten,这里是公式:

Relative absolute error formula absolute

Root relative squared error formula relative

  • Actual target values: a1 a2 … an
  • Predicted target values: p1 p2 … pn
问题回答

根相对平方错误的公式实际上是相对平方错误的公式。您需要选择此公式的平方根才能获得 Weka 输出的内容 。

Witten Weka书第177页,Ian H.,Eibe Frank和Mark A. Hall,“实用机器学习工具和技术”。 Morgan Kaufmann(2005年):578,相对方形错误的定义如下:

“错误是相对于使用简单的预测器时的错误。 有关的简单预测器仅仅是从 < 坚固 > 训练 < /坚固 > 数据中得出的实际值的平均值。 因此,相对的平方错误取总平方错误,并通过除以默认预测器的总平方错误来使其正常化。”

这与Weka执行一致,因此,人们需要计算所有相对错误的 " 强力 " 列车/强力 " 设定目标的平均值。





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