ExcelBanter - View Single Post - Even Distribution of Students now with a Weighted Twist

[email protected]

wrote:
Let me first start by saying that I am not the smartest
person in the world I learn everyday.

Actually, it is the smartest people that "learn everyday" ;-).

We have a poplulation of 1563 students.
Are program will only allow 1110 students. We have 3 tests we
work from. Test X has 146 students, test Y has 723 and test Z has 694.
Since we have only 1110 openings what I did was to divide the
1110/1563. This would give me a percentage of about 71.0172744721689%.
Then I took the figure and I divided each test group
146/71.0172744721689%, 723 /71.0172744721689% and the
694/71.0172744721689%. When rounded this gives me 104 children for test
X, 513 for test Y and 493 for text Z.

I think you multiplied, not divided, by 71%. For example, 146*71% ~=
104, but 146/71% ~= 206.

My question is, is there a way to
weight the different tests like test X =35%, test Y = 25% and test Z =
40% and have that come out to the 1110 students?

1110*35% (about 389) should come from test X. 1110*25% (about 278)
should come from test Y. 1110*40% (444) should come from test Z.

Note that that sums to 1111, not 1110. One way to ensure the proper
sum is to compute the last category not by 1110*40%, but effectively by
1110 - 389 - 278. It might also help to use so-called "banker's
rounding" (round xxx.50...0 to the nearest even number). But that does
not obviate the need to compute the last category in the aforementioned
manner in the general case -- albeit sufficient in this particular case
by coincidence.