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对于癌症检测的例子来说,y=1代表有癌症(1代表数目比较小的类) Precision/Recall \[\Pr ecision = \frac{{True \bullet positive}}{{predicted \bullet positive}} = \frac{{True \bullet p 阅读全文
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Rcommended approach Start with a simple algorithm that you can implement quickly. Implement it and test it on your cross-validation data. Plot learnin 阅读全文
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“Small” neural network (fewer parameters; more prone to underfitting) Computationally cheaper "Large" neural network (more parameters; more prone to o 阅读全文
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学习曲线 “训练误差”和“交叉验证误差”如下 \[\begin{array}{l}{J_{train}}\left( \theta \right) = \frac{1}{{2{m_{train}}}}\sum\limits_{i = 1}^{{m_{train}}} {{{\left( {{h_\t 阅读全文