一道关于 precision、recall 和 threshold关系的机器学习题

Suppose you have trained a logistic regression classifier which is outputing hθ(x).

Currently, you predict 1 if hθ(x)≥threshold, and predict 0 if hθ(x)<threshold, where currently the threshold is set to 0.5.

Suppose you increase the threshold to 0.7. Which of the following are true? Check all that apply.

 The classifier is likely to now have higher recall.

 The classifier is likely to now have higher precision.

 The classifier is likely to have unchanged precision and recall, and thus the same F1 score.

 The classifier is likely to have unchanged precision and recall, but higher accuracy.

 

这道题变着花样做了好几遍，老是做错啊。。。

给点思路吧。。。哭。。。