Ranking question with different number of observations?

[wc115]

I need to rank multiple "subjects" such as listing the "subjects" from best to worst. <--not sure if subject is the correct term.

example: school A and school B

school A has 10 students with an average score of 100%
school B has 30 students with an average score of 98%

which school would be better or ranked higher? Is there a formula i can apply?
a formula that I can use when there are hundreds or thousands of schools?I feel that school B would be better... because there are more students?
I was thinking of using a weighted formula such as: students x weight(70%) + scores(30%) = final score

and then rank the schools from highest final score to lowest score

but the use of weights would be subjective...is there another method that i may use?

thank you

 

[fresh_42]

No, you intend to assign a single number to a set of values. Since there is no natural way which connects the different values, there is neither a natural way to combine them. Thus a subjective weight function is your only possibility.