Michiko entered a class seeing her seatmate Yesha crying asked her what makes her cry. Yesha answered " I got a grade if 75 in Physics. Then Michiko saw her other seatmate Yuan smiling and very happy...

Michiko entered a class seeing her seatmate Yesha crying asked her what makes her cry. Yesha answered " I got a grade if 75 in Physics. Then Michiko saw her other seatmate Yuan smiling and very happy asked him why he is happy. Yuan answered " I got a grade of 75 in Biology. Michiko got back to Yesha and told her. " You do not have a reason to be sad. Take a look at Yuan. He got the same grade of 75 in Biology, yet he is happy wit it. Can' t you be happy like Yuan? Is michiko correct in her statement to Yesha? With your knowledge in z-scores as a standard score. What other parameter/values known here before we can justify Michiko Statement. With the known parameters now ,how can you justify ( or criticize) Michiko in her statement of comparing the test performance of Yesha and Yuan?

Hope someone will help me to answer this!

Thank you.