How do we select the threshold?

#1

In this problem, we have taken 0.5 as the threshold but how do you know to select 0.5?

#2

hey @lintasheelkumar ,
0.5 is selected as general value to distinguish between two things.
either one or another , 50% chances for both.

Although you can change it too based on your liking , it is no hard rule that it needs to be 0.5 only.
I hope this helps.