| Posted by | Message |
iPadThai 
New Orleans Saints Fan
Member since Oct 2011
625 posts
| Weighted average problem with negative numbers (Posted on 11/29/12 at 11:47 pm)
Let's say I have 4 values A, B, C and D. Let's say they each contribute 30%, 30%, 20% and 20% towards some final value.
So my weighted average formula is:
X = [0.3(A) + 0.3(B) + 0.2(C) + 0.2(D)] / [0.3+0.3+0.2+0.2]
But what if the situation is such that values C and D contribute negatively to the over all value X?
As a sports analogy using a hypothetical situation, let's say I am calculating a Quartback's rating using my own method as follows:
A = Yards/Attempt (I want this to be high, so this is a positive value) - 30% weight
B = Touchdown percentage (I want this to be high, so this is a positive value) - 30% weight
C = Number of incomplete passes (I want this number to be low/minumum and it contributes negatively to the overall rating) - 20% weight
D = Interception percentage (Needs to be minimized and contributes negatively to the overall rating) - 20% weight
So for my overall weighted average QB rating can I use this formula?
X = [0.3(A) + 0.3(B) - 0.2(C) - 0.2(D)] / [0.3+0.3+0.2+0.2]
If this is wrong, how to I account of positive and negative numbers in the same weighted average formula?
This post was edited on 11/29 at 11:51 pm
|
| Back to top | Share on  |
hg 
Toledo Fan
Member since Jun 2009
53215 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:48 pm to iPadThai)
|
| Back to top | |
JLSIX
New Orleans Saints Fan
New Orleans, LA
Member since Apr 2010
15392 posts
 Online
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:48 pm to iPadThai)
288
|
| Back to top | |
TigerHam85 
Hawaii Fan
Waimea Bay, HI
Member since Nov 2009
16949 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:48 pm to iPadThai)
288
eta: damnit!
This post was edited on 11/29 at 11:49 pm
|
| Back to top | |
Joe 
LSU Fan
North Jersey
Member since Jan 2005
5711 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:48 pm to iPadThai)
The plane takes off.
This post was edited on 11/29 at 11:49 pm
|
| Back to top | |
Hazelnut 
LA-Lafayette Fan
The Flatts
Member since May 2011
9650 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:49 pm to iPadThai)
TL,DR
Too Late, didn't read
|
| Back to top | |
KosmoCramer 
Ohio State Fan
Member since Dec 2007
40078 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:50 pm to iPadThai)
288
|
| Back to top | |
Harry Caray
LSU Fan
Team Boxtard Grounds Crew
Member since Aug 2009
10639 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:50 pm to iPadThai)
quote:
X = [0.3(A) + 0.3(B) - 0.2(C) - 0.2(D)] / [0.3+0.3+0.2+0.2]
well, this leaves your maximum possible rating at 60%
ETA: 288
This post was edited on 11/29 at 11:51 pm
|
| Back to top | |
iPadThai
New Orleans Saints Fan
Member since Oct 2011
625 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:52 pm to Harry Caray)
quote:
well, this leaves your maximum possible rating at 60%
That is what I am afraid I am doing wrong.
How can I account for the positive and negative weights at the same time while making sure they add up to 100%?
|
| Back to top | |
lsu480 
Arizona State Fan
1488 posts
Member since Oct 2007
48088 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:54 pm to iPadThai)
It's 2
|
| Back to top | |
Vicks Kennel Club 
USA Fan
In Spielman We Trust
Member since Dec 2010
12734 posts
Online
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:55 pm to iPadThai)
Why do you keep writing the denominator? It is just one in your formula.
|
| Back to top | |
Harry Caray
LSU Fan
Team Boxtard Grounds Crew
Member since Aug 2009
10639 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:55 pm to iPadThai)
quote:
How can I account for the positive and negative weights at the same time while making sure they add up to 100%?
idk, take a class.
ETA: study the passer rating stat...even though it maxes out at 158.3 instead of 100, it'll give you an idea.
This post was edited on 11/29 at 11:58 pm
|
| Back to top | |
au21tigers 
Auburn Fan
Huntsville
Member since Nov 2009
3762 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:56 pm to iPadThai)
LINK
|
| Back to top | |
ConwayTwizzle 
Alabama Fan
Little Havana
Member since Nov 2012
1887 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:56 pm to iPadThai)
tl;dr but it's either 2 or 288 
|
| Back to top | |
Vicks Kennel Club
USA Fan
In Spielman We Trust
Member since Dec 2010
12734 posts
Online
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:56 pm to lsu480)
quote:
It's 2
I probably made some of my best arguments ever in that thread.
|
| Back to top | |
lsu480
Arizona State Fan
1488 posts
Member since Oct 2007
48088 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:57 pm to Vicks Kennel Club)
|
| Back to top | |
Gator5220 
Florida Fan
Member since Aug 2010
362 posts
| re: Weighted average problem with negative numbers (Posted on 11/29/12 at 11:57 pm to iPadThai)
I'll take a whopper no onion please.
|
| Back to top | |
Macintosh504 
Maryland Fan
Member since Sep 2011
15264 posts
Online
| re: Weighted average problem with negative numbers (Posted on 11/30/12 at 12:00 am to Harry Caray)
288
yes, I'm a genius
|
| Back to top | |
iPadThai
New Orleans Saints Fan
Member since Oct 2011
625 posts
| re: Weighted average problem with negative numbers (Posted on 11/30/12 at 11:01 am to Macintosh504)
Can somebody from the day crew weigh-in with their thoughts please? Thanks.
|
| Back to top | |
