# Tournament variance

• Bronze
Joined: 20.02.2015
Hey guys,

I have a few questions about variance that I'd like to clear up.

I play 9man turbo STTs so I'll be asking specifficaly for this kind of tournaments.

1. Firstly I want to ask how accurate really is Pokerdope tournament variance calc.?

Since it doesn't have a built in ITM% option and also just assumes that the places distribution is equal for 1,2 and third place... For example:

I put in 2000 5+0.5\$ STTs with 5% ROI

It gives me: Probability of loss: 6%
70% confidence interval 2-8%roi=180-900\$

Now, how accurate is this-how big deviations I can expect? And is there maybe any better variance calc for tournaments?

2. I've read THIS a cuple of times and I have a few questions that I hope you guys can help me out with..

a) I know it's hard to determine accurate ROI so I'm wondering how can be ROI confidance interval calculated, maybe with some calc?

Exmp: I have 8% ROI in 3500 STTs

Acordinng to this guy:
For example, a 3% eROI player only has about a 7% chance of winning as much as a 7% eROI player, so if you pull off a 7% eROI over 3k STTs, you can be fairly confident that your real eROI is at least 3% (and basically certain that you’re a winner). The 95% confidence interval still spans almost 11% (e.g. from -3% to 8% eROI), so you’re not going to get much useful information at that level of confidence. But, the 75% confidence interval spans about 6% (e.g. from 0% to to 6% eROI). That ain’t great, but it’s something.
SO there's a good chance I have at lest 3% roi if I understand corectly?
And with 95% confidance I have -3-8%? And with 75% confidance interval I have 0-6% ROI.

Now I wanna know how did this guy get this numbers so I can calculate for myslef?

b) If I have like 8% roi EV adjusted over 1k sample. Is EV adjsuted roi a lot more accurate when determining my true ROI-and how much?

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And lastly do pros actually calculate all this for themselves before turning pro or they just know what to expect from previous years..