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Median???
Serveur: Titan
Game: FFXI
Posts: 21
By Titan.Palesade 2008-12-04 15:48:27
How is median calculated on this site? Sometimes I see strangeness that I don't understand. My understanding of median was that it was the middle value when going by sheer count... so it is the number that has the same amount of data points above it as it does below it.
Why then am I see this? Look up Beetle Mittens +1 on Titan. Here's the data in case in changes by the time you read this...
Median is currently at 1000.
Below are the previous sales. You'll notice that a single sale was for 1k, and it happens to be the second most recent sale. EVERY other sale is much higher than 1k. How can median be 1k?
Dec. 2, 2008 Blessedangel Valerie 9,000 Dec. 1, 2008 Anslem Yangasu 1,000 Nov. 30, 2008 Lamont Linku 8,000 Nov. 30, 2008 Daffelz Anslem 10,000 Nov. 29, 2008 Angelsola Turell 8,000 Nov. 29, 2008 Weeeeeee Kryll 8,000 Nov. 29, 2008 Vanon Blessedangel 8,000 Nov. 28, 2008 Riddik Socant 8,000 Nov. 28, 2008 Halhal Donkie 7,000 Nov. 24, 2008 Antique Skyfang 8,000 Nov. 24, 2008 Maine Quma 8,000 Nov. 23, 2008 Halls Boochan 8,000 Nov. 23, 2008 Mindhunter Shunsho 8,200 Nov. 23, 2008 Hattori Popp 8,100 Nov. 22, 2008 Spert Zicdeh 8,000 Nov. 21, 2008 Nyny Laucredant 8,000 Nov. 19, 2008 Ayaha Godfrey 8,000 Nov. 19, 2008 Hilti Sonofagun 8,000 Nov. 19, 2008 Ilaunie Hilti 10,000 Nov. 18, 2008 Pocopen Orick 8,000 Nov. 17, 2008 Jorg Weeeeeee 8,000 Nov. 17, 2008 Clavia Garnetdagger 8,000 Nov. 17, 2008 Sumopwr Qumar 8,000 Nov. 16, 2008 Ophelia Sapi 8,000 Nov. 14, 2008 Gerita Exio 8,000
Serveur: Titan
Game: FFXI
Posts: 21
By Titan.Palesade 2008-12-04 15:50:23
In fact, in every example I've looked at, the "Median" value is simply the second most recent sale price. What the heck is up with that? Am I crazy?
Serveur: Titan
Game: FFXI
Posts: 21
By Titan.Palesade 2008-12-04 15:51:22
Tiger Hunter on Titan is another great example. Media currently reads an odd 2,360.
Previous sales are...
Dec. 3, 2008 Oxo Palesade 5,000 Dec. 2, 2008 Zeld Silversterr 2,360 Nov. 30, 2008 Slasher Hachishiki 4,000 Nov. 30, 2008 Slasher Lomyou 4,000 Nov. 28, 2008 Pifre Darkdart 4,000 Nov. 25, 2008 Hakugen Pfeffernuse 4,000 Nov. 25, 2008 Optimus Pifre 4,000 Nov. 23, 2008 Turell Oxo 6,000 Nov. 22, 2008 Waterlegend Kratos 5,000 Nov. 20, 2008 Toraneco Warlordd 6,000 Nov. 20, 2008 Tuntunmaru Nung 4,000 Nov. 20, 2008 Tuntunmaru Nung 4,000 Nov. 19, 2008 Optimus Jollymike 4,000 Nov. 19, 2008 Teretha Jollymike 4,000 Nov. 17, 2008 Zoos Tuntunmaru 4,000 Nov. 17, 2008 Friendless Tuntunmaru 4,000 Nov. 15, 2008 Junjix Souga 4,000 Nov. 15, 2008 Aqri Fushu 3,000 Nov. 15, 2008 Ryozo Chabs 3,000 Nov. 15, 2008 Digi Jerusalem 3,000 Nov. 14, 2008 Ruinator Amdukias 4,000 Nov. 13, 2008 Amulet Digi 3,000 Nov. 13, 2008 Amulet Junna 3,000 Nov. 11, 2008 Tomotoro Friendless 5,100 Nov. 11, 2008 Tamanegi Higemegane 6,000
Serveur: Titan
Game: FFXI
Posts: 21
By Titan.Palesade 2008-12-04 16:10:01
Strangely, Beetle Mittens +1 have now switched to reading 8k... but I swear it was 1k!
Serveur: Titan
Game: FFXI
Posts: 21
By Titan.Palesade 2008-12-04 16:11:21
Well everything seems back to reasonable numbers again. I'm not crazy, I swear. =P
Fenrir.Scragg
Administrator
Serveur: Fenrir
Game: FFXI
Posts: 2579
By Fenrir.Scragg 2008-12-04 16:17:02
lol. gotcha
Thanks for reporting. An important part of the median calculation was left out... could of sworn it was there before. As of right now, it takes the median of the last 3 transactions, good for fast selling items... bad for the slow sellers. This only applies for the Median displayed on the item pages.
Medians displayed everywhere else is a precomputed based on the last 25 transactions if I'm not mistaken.
How is median calculated on this site? Sometimes I see strangeness that I don't understand. My understanding of median was that it was the middle value when going by sheer count... so it is the number that has the same amount of data points above it as it does below it.
Why then am I see this? Look up Beetle Mittens +1 on Titan. Here's the data in case in changes by the time you read this...
Median is currently at 1000.
Below are the previous sales. You'll notice that a single sale was for 1k, and it happens to be the second most recent sale. EVERY other sale is much higher than 1k. How can median be 1k?
Dec. 2, 2008 Blessedangel Valerie 9,000 Dec. 1, 2008 Anslem Yangasu 1,000 Nov. 30, 2008 Lamont Linku 8,000 Nov. 30, 2008 Daffelz Anslem 10,000 Nov. 29, 2008 Angelsola Turell 8,000 Nov. 29, 2008 Weeeeeee Kryll 8,000 Nov. 29, 2008 Vanon Blessedangel 8,000 Nov. 28, 2008 Riddik Socant 8,000 Nov. 28, 2008 Halhal Donkie 7,000 Nov. 24, 2008 Antique Skyfang 8,000 Nov. 24, 2008 Maine Quma 8,000 Nov. 23, 2008 Halls Boochan 8,000 Nov. 23, 2008 Mindhunter Shunsho 8,200 Nov. 23, 2008 Hattori Popp 8,100 Nov. 22, 2008 Spert Zicdeh 8,000 Nov. 21, 2008 Nyny Laucredant 8,000 Nov. 19, 2008 Ayaha Godfrey 8,000 Nov. 19, 2008 Hilti Sonofagun 8,000 Nov. 19, 2008 Ilaunie Hilti 10,000 Nov. 18, 2008 Pocopen Orick 8,000 Nov. 17, 2008 Jorg Weeeeeee 8,000 Nov. 17, 2008 Clavia Garnetdagger 8,000 Nov. 17, 2008 Sumopwr Qumar 8,000 Nov. 16, 2008 Ophelia Sapi 8,000 Nov. 14, 2008 Gerita Exio 8,000
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