Notes from chapter 3 of Neural Networks and Deep Learning Measurements of fit From Neural Networks and Deep Learning, 4 measures of the same data to check how good the fit is: Here accuracy on the test data plateaus around epoch 280, while the training data cost keeps going down smoothly. On the other hand, the cost for the test data starts going up around epoch 15, which is more or less the same point that the accuracy on the training data stops drastically improving.
