Thank you :))

Starting from 0 doesn't improve the chart reading much since his dad is already thinking in terms of area.

A 60% point vs 70% point bar would just lead his dad to think it is a improvement of 1/6 times but for such tests that are scored out of 100% we should be thinking in terms of % points instead.

I.e a 10% point improvement.


Thinking in terms of the number of times does not quite demonstrate improvement well.

Eg. If I score 3% points for test 1 and 30% points for test 2, I have improved by 9 times by this perspective, and that phrase '9 times' seems like a lot.

But actually, it is only a 27% point increase , which is rather insignificant since I still failed (assuming the passing mark is 50%)