误差评估标准

	Actual 1	Actual 0
Predicted 1	True Positive	False Positive
Predicted 0	False Negative	True Negative

**Precision = True Positive / #Predicted Positive = True Positive / True Positive + False Positive **

**Recall = True Positive / #Actual Positive = True Positive / True Positive + False Negative **

Accuracy = (true positives + true negatives) / (total examples)
Precision = (true positives) / (true positives + false positives) predicted
Recall = (true positives) / (true positives + false negatives) actual 1
F1 score = (2 * precision * recall) / (precision + recall)

Predict y=1 if h_theta(x) >= threshikd

F₁ score = 2*(PR/ P+R)