i need an answer in statisticts

[memas]

i want to ask
1... having two groups of students can we decide which group is better than the other according to their values from the school examination ?
2...how accurate will be the answer in percentage
3...and which are the analysis we need for that
thank you
memas

[jemidiah]

(1) What *exactly* do you mean by "better"? The answer to all three questions hinges on that definition.