Rules for main forums
- Be nice
- No advertisement
- No events
- No fundraisers
- No topics asking for votes
- Only posts related to Brazilian Jiu Jitsu
Average belt time diluted and possible outlier removal
6 year(s) ago • 12865 views • 11 replies
JEWhite beltVerified
6 year(s) ago
Hi,
The belt statistics page shows stats on students with Top20s of belt times. I was clicking through it it seems like a number of those use the white belt start as the date they did anything grappling related, not when they actually started training BJJ. Great that you wrestled as a teenager, but that is not when you started JBB :D
The top20 white belts are from 40 to 15 years. Is the average calculated over the whole population or are outliers removed at the top and bottom? I know it is a bit of a nerd question. Sorry. :)
The belt statistics page shows stats on students with Top20s of belt times. I was clicking through it it seems like a number of those use the white belt start as the date they did anything grappling related, not when they actually started training BJJ. Great that you wrestled as a teenager, but that is not when you started JBB :D
The top20 white belts are from 40 to 15 years. Is the average calculated over the whole population or are outliers removed at the top and bottom? I know it is a bit of a nerd question. Sorry. :)
![Slideyfoot [jun]](userimg/5e25cf311adfd.jpg){kind=small}
SJBlack belt 1st degreeVerified
6 year(s) ago
The belt statistics page shows stats on students with Top20s of belt times. I was clicking through it it seems like a number of those use the white belt start as the date they did anything grappling related, not when they actually started training BJJ. Great that you wrestled as a teenager, but that is not when you started JBB :D
Yeah, a lot of people have filled that in wrong. It irks my nerdiness too, but meh. Given the average belt stats seem quite reasonable, I'm assuming they haven't massively skewed as a result anyway. I would guess either outliers (like the "40 year white belt who really wasn't, it definitely wasn't BJJ" guy) have been removed, or they aren't having much of an impact on the overall stats. I could be wrong.
JEWhite beltVerified
6 year(s) ago
Nerds unite, lol.
It probably doesnt impact the overall, as all verified adult users ~4000 have whitebelt stats.
Still curious how it is currently calculated though. :)
It probably doesnt impact the overall, as all verified adult users ~4000 have whitebelt stats.
Still curious how it is currently calculated though. :)
Edited 6 year(s) ago
AKPurple beltVerified
CGBlack belt 4th degreeVerified
6 year(s) ago
We debated this a lot back in January and ultimately decided to include everything in the stats, including outliers :)
JEWhite beltVerified
6 year(s) ago
Ah, so they are in there. Thanks for replying.
AKPurple beltVerified
6 year(s) ago
We debated this a lot back in January and ultimately decided to include everything in the stats, including outliers :)
I'd like to see the minutes of that debate please
JFBlack beltVerified
4 year(s) ago
This person spent 2012 years as a white belt! Maybe we should at least remove the immortals so the don’t skew the data for us humans….z
CGBlack belt 4th degreeVerified
4 year(s) ago
This person spent 2012 years as a white belt! Maybe we should at least remove the immortals so the don’t skew the data for us humans….z
The statistics only include verified profiles. So if there's an error on a profile, the community can downvote it and thereby exclude it from the stats :)
NHBlue beltVerified
3 year(s) ago
How is the average time calculated? Is it a median or a mean?
JSPurple beltVerified
3 year(s) ago
Using the median instead of the average would be more robust to outliers and would not require their exclusion
Edited 3 year(s) ago
