
Any mathemeticians?
We recently wrote a school grading app that used both weighted and nonweighted grades in their classes.<BR><BR>One of the teachers had 4 categories in a class, each weighted at 25%. Not that it changed the app but the question was, isn't that the same as a nonweighted class? Everyone agreed it was. However, when we put numbers to calculator we found that if you took the same grades and figured it as a weighted and a nonweighted class, using 25% for each category, the nonweighted can figure out to be up to 2% higher than the weighted.<BR><BR>Anyone care to take a stab at explainign this to poor dumb me?

Show an example???
It might just be rounding errors? Or an error in your algorithm, even.<BR><BR>Mathematically, it *HAS* to be the same:<BR><BR>sum = 0.25 * grade1 + 0.25 * grade2 + 0.25 * grade3 + 0.25 * grade4 <BR><BR>*is* exactly the same as<BR><BR>sum = ( grade1 + grade2 + grade3 + grade4 ) / 4<BR><BR>since of course 1/4 is the same as 0.25.<BR><BR>I suspect cockpit error.<BR><BR><BR><BR>

p.s. My degree is in Math...
...but that was mumbletymumble years ago.<BR><BR>

RE: p.s. My degree is in Math...
mumbletymumble?<BR><BR>Gees, you are old ;)<BR><BR>Craig.

OK
here is one of the examples we tried.<BR><BR>Homework (25%) 92%  87.5%  83%  100%<BR>Quiz (25%) 78%  92.5%<BR>Test (25%) 63%  93%  87.5%<BR>Class (25%) 92%  86%<BR><BR>OK if the class were not weighted the grade would be: 86.77%<BR><BR>If we used a wieghted formula the grade would be: 86.5%<BR><BR>The nonwieghted is the total of the grades/# of grades<BR><BR>The weighted is the total in each category/# of grades in that category. Add the resulting total and divide by 4 since that, in this case, is 25% for each category.<BR><BR>Now unless they told us incorrectly that is the way to figure a weighted grade.<BR><BR>And yes I knew you majored in math and hoped you would see this. While I don;t have a mathematics degree this doesn't make sense to me. It should, as you state, be exactly the same. I would love to prove the teacher's and the principal wrong so do tell.

Actually...
...I didn't get my degree until age 27. (4 years in USAF in the middle there, then working full time while finishing off degree half time.)<BR><BR>So mumbledymumble doesn't reveal my real age, by 5 years.<BR><BR>

So you're actually....
mumbledymumble + 5?<BR><BR>;)<BR><BR>Craig.

Sheesh
using your formula I come out with 86.51%<BR><BR>What the heck???<BR><BR>This should not be that tough for me. I'm not an idiot despite proof to the contrary.

Well, ready to feel silly?
Homework (25%) 92%  87.5%  83%  100%<BR>Quiz (25%) 78%  92.5%<BR>Test (25%) 63%  93%  87.5%<BR>Class (25%) 92%  86%<BR><BR>Homework average: 90.625<BR>Quiz average: 85.25<BR>Test average: 81.16666666667<BR>Class average: 89.0<BR><BR>Sum of those: 346.04166666666667<BR><BR>Divided by 4: 86.5104166666667<BR><BR>***********<BR><BR>25% of Homework average: 22.65625<BR>25% of Quiz average: 21.3125<BR>25% of Test average: 20.2916666666667<BR>25% of Class average: 22.25<BR><BR>Sum of those: 86.5104166666667<BR><BR>Sure look identical to me.<BR><BR>I would have to assume that somewhere along the way you ROUNDED some of the numbers. Nope. Can't do that. If you use DOUBLE arithmetic in VBScript (accuracy of 14 or more decimal digits) you should get the same final rounded result, even if you round to 6 or 8 digits or more.<BR><BR>If you were doing this on a stupid desktop calculator that rounds every result to only 2 digits after the decimal point, then no wonder you got different results.<BR><BR><BR>

RE: So you're actually....
Clng(mumbledymumble + 5)<BR><BR>Note: Not Cint!
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