Question

[Xtaki]

Let's say I have a list of students and each student evaluate by two categories:

Student 1: Category A - 1, Category B - 51
Student 2: Category A - 3, Category B - 60
Student 3: Category A - 4, Category B - 62
Student 4: Category A - 3, Category B - 68
Student 5: Category A - 2, Category B - 65
Student 6: Category A - 9, Category B - 71
Student 7: Category A - 3, Category B - 53
Student 8: Category A - 2, Category B - 57
Student 9: Category A - 2, Category B - 53

I want to rank them using those two categories.
The formula that I did is:

[Student_i_CategoryA - Min(CategoryA)] / [(Max(CategoryA) - Min(CategoryA)] + [Student_i_CategoryB - Min(CategoryB)] / [(Max(CategoryB) - Min(CategoryB)]

For example:
Student 3 value is:
(4 - 1) / (9 - 1) + (62 - 51) / (71 - 51) = 0.925

the value that I got is always between 0 and 2

My question is:
Is there a better formula to use? I see that in category A the number 9 is much bigger than the other numbers maybe there is a different formula in this case

Thank you!

 

[Dr.Peterson]

Let's say I have a list of students and each student evaluate by two categories:

Student 1: Category A - 1, Category B - 51
Student 2: Category A - 3, Category B - 60
Student 3: Category A - 4, Category B - 62
Student 4: Category A - 3, Category B - 68
Student 5: Category A - 2, Category B - 65
Student 6: Category A - 9, Category B - 71
Student 7: Category A - 3, Category B - 53
Student 8: Category A - 2, Category B - 57
Student 9: Category A - 2, Category B - 53

I want to rank them using those two categories.
The formula that I did is:

[Student_i_CategoryA - Min(CategoryA)] / [(Max(CategoryA) - Min(CategoryA)] + [Student_i_CategoryB - Min(CategoryB)] / [(Max(CategoryB) - Min(CategoryB)]

For example:
Student 3 value is:
(4 - 1) / (9 - 1) + (62 - 51) / (71 - 51) = 0.925

the value that I got is always between 0 and 2

My question is:
Is there a better formula to use? I see that in category A the number 9 is much bigger than the other numbers maybe there is a different formula in this case

Thank you!

It depends on the importance of the two categories for your purposes.

If the categories were height and weight, the basketball coach (who likes tall students), the football coach (who wants heavy students), and the school nurse (who likes students whose weight matches their height) would likely rank them very differently for their purposes.

But if you weight the two categories equally, and if the scoring is reasonable, then your formula seems good; in effect, you are averaging the two relative scores. The fact that one student got a 9 may skew the results; one way to avoid that would be to go not by the range in this group, but by a theoretical range if one exists.