1000 hour sample size

goodguy_1 · #1 10-15-2003, 05:30 PM

I am reposting this part of a post on th internet forum to get some feedback from the math wonks over here [img]/images/graemlins/smile.gif[/img]

"Btw I passed 1000 hours online in my main limit game about 3 months ago.
You would think after a 1000 hours your winrate would be fairly accurate.Well my hourly average fell 18% in the next 2 months which blew me away..now it's back up there ..but just goes to show you how insignificant sample sizes are of 100,200 even 500 hours.BruceZ help or Homer???
How accurate should your winrate be after a 1000 hour sample size.I know its in one of Mason's PokerEssays books?Too lazy to investigate it. "

What's the probabity of my winrate falling 18% after a 1000 hour sample size??

thnx Lee

BruceZ · #2 10-15-2003, 07:01 PM

I recently posted about this here.

A change of 18% is nothing after 1000 hours. You only have 68% confidence that your hourly rate is even accurate to within 32% assuming your standard deviation is 10 times your hourly rate, so it can easily be off by even more than 32%. This is assuming there was no change in your competition or in the quality of your play. If you want it to be accurate to within 18%, you'd have to play 3086 hours to have a 68% confidence of being that accurate. If you want a 90% confidence, then you'd have to play 7901 hours.

goodguy_1 · #3 10-15-2003, 07:22 PM

Bruce I am surprised at how large these numbers are but I am happy to hear it ..kinda... lol..thnx for your timely assistance.

BruceZ · #4 10-15-2003, 07:39 PM

You also have to look at how many hours it took to drop 18%. If you lost a large amount in a short time, that could still be a low probability event, and it could make it likely that something changed. How many hours did you play in the 2 months following the 1000 hours?

goodguy_1 · #5 10-15-2003, 08:03 PM

Bruce: appreciate the follow-up here are the specifc numbers:

This is in $2-4 LHE.

On 7/17/03 my earn was $+8.31 per hour on 949.92 hours.On 10/08/03 my average bottomed out at $+6.89 per hour on 1251.37 hours.So in 301.45 hours my average fell 17.08% right now this average has bounced back to $+7.72 on 1291.99 total hours.I usually play 2-3 these games at once.Thanx bruce for the feedback [img]/images/graemlins/smile.gif[/img]