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a report on the July percentage errors
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skrumgaer wrote
at 4:07 PM, Wednesday July 30, 2008 EDT
moneymango reported that the percentages for July for first through seventh place sum to only 85% or so.
From doing the stats for my own games, I reach the following diagnosis: 1. The percentages and number of games reported daily are correct. 2. The number of games reported monthly is correct. 3. The error is distributed proportionally across all places of finish, but because of truncation of percentages, the proportion of error is likely to be larger for smaller percentages. 4. Multiply your percentages by 1.17 to get the best fit. |
Replies 1 - 9 of 9
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MadHat_Sam wrote
at 5:57 PM, Wednesday July 30, 2008 EDT This seem to start around monday as I noticed a drop in all my stats around then 1-2% for each place.
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Shevar wrote
at 6:46 PM, Wednesday July 30, 2008 EDT i agree with 1. and 2.
However the error is not distributed proportionally. on my profile: 1st 2nd 3rd 4th 5th 6th 7th 16% 7% 12% 9% 7% 13% 11% they add up to 75%. after calculating myself i got: 1st 2nd 3rd 4th 5th 6th 7th 22% 10% 13% 12% 11% 15% 15% so the error in my case distributes like this: 1st 2nd 3rd 4th 5th 6th 7th -8 -3 -1 -3 -4 -2 -4 weird... |
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skrumgaer wrote
at 9:25 PM, Wednesday July 30, 2008 EDT Shevar:
Your calculated percentages add up to 98%. The cause: fractional percentages are truncated (not rounded) to the next lower whole number. If a fractional percentage is lower to start with, the truncation more likely to be a bigger percentage of the number, so the bigger errors, in proportion, are likely associated with the smaller numbers. So your 7% and 9% are likely to show bigger changes in proportion compared to 22%. |
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moneymango wrote
at 10:18 PM, Wednesday July 30, 2008 EDT I'm down to 74%, im losing percentages... so i assume i multiply my percentages by 1.35?
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dasfury wrote
at 6:37 AM, Thursday July 31, 2008 EDT WOW. I'm at 77%
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UpmaxM wrote
at 6:51 AM, Thursday July 31, 2008 EDT y it started this week
before i had the "vacation" in the lands of Hyborea (meaning i played Age of Conan 2 weeks straight)i had 33% first, then i dropped to 32% and even though i had 38% of first yesterday my month 1st % dropped several % yesterday |
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UpmaxM wrote
at 6:52 AM, Thursday July 31, 2008 EDT i think it stopped adding % in the last few days - or morelike, it adds total games, but doesnt add any 1sts 2nds .... 7ths at all so it all begins to shrink
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Shevar wrote
at 7:00 AM, Thursday July 31, 2008 EDT ah yeah, i got it. the error strongly depends on the number of games played on a day. For instance if you play 10 or 5 games a day your percentages will be integers not affected by truncation. However if you play 9 games you will loose exactly 1%.
Why are the 7 monthly percentages not calculated directly from the number of the 7 ranks respectively? |
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Shevar wrote
at 7:01 AM, Thursday July 31, 2008 EDT lol
what max says might be true as well... |
