newtobj: Standard deviation

[newtobj]

I keep reading articles about standard deviation but each one uses a different formula. Can anyone tell me what the correct formula for calculating the standard deviation of N is? Where N is the number of hands.

[Don Schlesinger]

> I keep reading articles about standard
> deviation but each one uses a different
> formula. Can anyone tell me what the correct
> formula for calculating the standard
> deviation of N is? Where N is the number of
> hands.

Are you flat betting? Otherwise, the question can't really be answered without more information concerning your bet scheme.

Don

[newtobj]

> Are you flat betting? Otherwise, the
> question can't really be answered without
> more information concerning your bet scheme.

> Don

Yes. Then, if I were spreading 1 to 15, how would I calculate SD for the same 100 hands?

[Don Schlesinger]

> Yes. Then, if I were spreading 1 to 15, how
> would I calculate SD for the same 100 hands?

Depending on rules, for flat betting, SD equals about 1.15 times your bet size multiplied by the square root of the number of hands played.

If you spread, you need to know the frequencies of the true counts at which you make different bets. Then you square the bet sizes, multiply each by its frequency, multiply again by the variance (about 1.32), sum vertically, and take the square root of your answer. Alternatively, you can skip the variance part, wait until the end, and just multiply by 1.15.

Don

[newtobj]

Thanks Don. Now I'll know what range a session is likely to fall in.

[newtobj]

> Depending on rules, for flat betting, SD
> equals about 1.15 times your bet size
> multiplied by the square root of the number
> of hands played.

I did some calculations, assuming super conservative play - flat betting, no doubling down, no spliting, no spreading, or progressions and perfect basic strategy. Do these calculations seem accurate?

For 100 hands at a $10 min. table:

1 SD -105 to +95

2 SD -205 to +195

3 SD -305 to +295

For 100 hands at a $25 min. table:

1 SD -262.50 to +237.50

2 SD -512.50 to +487.50

3 SD -762.50 to +737.50

For 100 hands at a $5 min. table:

1 SD -52.50 to +47.50

2 SD -102.50 to +97.50

3 SD -152.50 to +147.50

[Don Schlesinger]

> I did some calculations, assuming super
> conservative play - flat betting, no
> doubling down, no spliting, no spreading, or
> progressions and perfect basic strategy. Do
> these calculations seem accurate?

You're assuming that if you do nothning at all to put more money on the table, the SD per hand will just be 1.00. It won't, because naturals pay 3 to 2 whether you like it or not! But, your numbers would be close to being correct.

However, never splitting or doubling is not "conservative" play, it's stupid play. So, you can't say you're playing "perfect" BS.

Don

[newtobj]

> You're assuming that if you do nothning at
> all to put more money on the table, the SD
> per hand will just be 1.00. It won't,
> because naturals pay 3 to 2 whether you like
> it or not! But, your numbers would be close
> to being correct.

> However, never splitting or doubling is not
> "conservative" play, it's stupid
> play. So, you can't say you're playing
> "perfect" BS.

> Don

Right. My mistake, I should have used the 1.15 instead of 1. That would give the following numbers:

For 100 hands on a $10 table

-120 to 110

-235 to 225

-350 to 340

For 100 hands on a $25 table

-300 to 275

-587.50 to 562.50

-875 to 850

These numbers are probably more accurate. Also, I was speaking theoretically about not doubling down or splitting, for the sake of the discussion. I agree it would be a foolish way to play.