Interpreting Std. Deviation

[Hombre]

Ok, so today I analyzed my last 66 recorded poker sessions and here's what I came up with. This is somewhat long.

In HPFAP the intro mentions using std. dev as a measure of short-term luck when compared to the win rate.
What is a good raio?

The authors mention "once you have achieved expert status, hold em offers an excellent relationship."

So my sample size may be a little small but I have some general questions. Not all of my observations were recorded at the same limit, should I omit these and only focus on the primary limit I play?

For the entire sample my win rate was $16.59 per hour with a Std. Dev of 141.941 and a ratio of 0.12

I omitted my largest win and loss which were both played at a higher limit and my numbers changed quite a bit.

Win rate increased to $18.61 per hour with a Std. Dev of 112.499 and a ratio of 0.17.

Can anyone please help me interpret this. What do the authors mean by an excellent ratio (relatively low risk but what number specifically is acceptable). If you are above or below a certain number is there any indication that you are "running good"?

If it is any help there were 14 losing sessions and 52 winning sessions for a winning % of 78.78.

Thanks

---Hombre

[Nottom]

Most people would prolly do the ratio the other way.

$112:$18.6 -> 6:1

This is a pretty good number. In live play a good play would expect a ratio of 8-10:1 on line that lowers a bit due to the increased rate of play, so between 5-7:1 is probably good.

Std Deviation doesn't really indicate that you are running good or bad, but is useful for determining BR requirements or analyzing how accurate your win rate may be. If it is low you play a low variance game, while if it is high you are probably a bit more likely to push a small edge or are a bit more loose or aggressive.

I'm not sure of how other poker games compare to hold'em, but would be interested in any numbers other posters could share.

[mr_jmac]

Hey,

1. Standard Deviation is just a statistical term that is related to a more commonly known statistical term, the mean (or average.) The standard deviation can help you "find the story behind your data. The standard deviation is a statistic that tells you how tightly all the individual data points are clustered around the mean in a set of data.

An example of a set of data is a bunch of test marks in school. You can find your average for all your test marks, say 70%. The standard deviation of the data can give us further information.

If the standard deviation is relatively low this means that most of the data is close to the average (i.e there is not much variation). In our example this would be a student who's marks are always close to 70% (maybe as high as 80% and as low as 60%).

If the standard deviation is relatively large this means that the data is more scattered (more variation). In our example, a student who on one test could get perfect and on another could bomb out and get 15%.

So, the standard deviation gives us more information about our data then simply the average (mean).

An example relating to poker is a wild, crazy and loose poker game vs a tight/passive game. The standard deviation for the latter type of game will be much lower. In the first type of game you will have huge winning sessions and huge losing sessions. In the second game your results will tend to be closer to the average.

2. What is a good ration between winrate (average) and standard deviation?

I don't really know if you can define a "good ratio". There is no ratio to aim for. It will depend on the type of game you are playing in and your playing style. Most good players tend to have a standard deviation in the range of 10-12 x the big bet of the game.

3. Yes, when calculating standard deviation you should only include one limit. Standard deviation measures the variance of data around one mean. If you combine you are coparing apples and oranges.

4. What do the authors mean by "excellent ratio?" Well, as we all know, poker is a game with a certain element of luck. You will have fluctuations in your results. Poker is a game which has a good size luck factor (that's what keeps the fish coming back ... they have to win sometimes). What the author's mean is that this luck factor is not too large. Sure you will suffer some bad streaks but you won't go on a ten year losing streak.

For example, suppose there was a positive expectation lottery with only one winner. This would not provide a good ratio between winrate and standard deviation. Why, because even though you have a positive expectation, you don't actually make any money until you hit the jackpot and chances are you never will in a lifetime.

Poker offers just the right ratio. The standard deviation of poker results is high enough such that even bad players can have winning streaks. This keeps them coming back. IF the ratio so low that good players won 99 out of 100 times and bad players won 1 out of 100 times there wouldn't be any good poker games.

5. The ratio between win rate and standard deviation doesn't tell you if you are running good or not. Your results do.