4. Binary Classification

I'm sorry, your answer is not correct.

• The recall goes up is incorrect. Precision and recall are inversely correlated to the threshold. We can only make the recall go up by adjusting the threshold to lower the precision.
• The recall stays the same is incorrect. Precision and recall are inversely correlated to the threshold. They will always move in opposite directions when the threshold changes.
• The recall goes down is correct
• It's impossible to say is incorrect. The behavior of precision and recall when the threshold changes is well known.