Math CentralQuandaries & Queries


Question from Cori, a teacher:

Ok, here goes: I teach a class in which there are seven projects/quizzes worth 10% each, and the midterm and the final are each worth 15%. No problem figuring out their final grade, but I have to give a mid-term average, having only FOUR of the seven 10% things, and the midterm test. The closest I've come to an accurate "average" is to just add them together (as equals) and average them. I'm looking for a formula to put in my Excel worksheet.

Can you help? Thank you for your time,


Cori, we have two responses for you:

Hi Cori,

The best you can do is average them. That is what the students are averaging at that moment anyway. Just add the four percents (out of 100) together and divide by four. For example if a student got 50%, 60%, 70% and 80%, then his average would be (50+60+70+80)/4.

In Excel it depends on how you have the data recorded. Basically,for each midterm you want (MtScore/MarksPossible*100). Add the four of these together and divide by 4.




What I have done in this situation is to take a student's score on a 10% quiz, divide by the maximum possible score on that quiz and multiply by 10. This gives a score out out 10. Do this for each of the quizzes and for the midterm but in this case multiply by 15 to give a score out of 15. Add the resulting four quiz scores and the midterm score to give a mid-term grade out of 55. If you want to express this as a percentage, divide by 55 and multiply by 100.

I hope this helps,
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