Down 1000 units in 200 hr of counting

B

bj21abc

Well-Known Member
No, no NO ! (actually yes if you were discussing anything else, not in this case - this is a specific heads-up question of 1x100 vs 2x75...)

Why do we place 75% of our single-hand bet on each of our two hands ?
Why not 50% on each - then we get the same EV, but lower variance ! (in that specific round)

The answer is because 75% on each of two hands gives a very close approximation (exact number is 76%, I think ?) to the SAME variance you get for playing one hand at 100%. Don't believe me ? Sim x million shoes - once playing a single hand and once playing 2 hands @ 75% (both heads up). EV and variance should be just about the same.

This is blackjack 101... I can specifically remember Wong explaining this in a little bit of detail in Professional BJ, I am sure this can be found in any good BJ book.

D.

Martin Gayle said:
This is contradictory. More hands gives a bigger sample size which reduces variance.
Click to expand...
 
kewljason

kewljason

Well-Known Member
bj21abc said:
No, no NO ! (actually yes if you were discussing anything else, not in this case - this is a specific heads-up question of 1x100 vs 2x75...)

Why do we place 75% of our single-hand bet on each of our two hands ?
Why not 50% on each - then we get the same EV, but lower variance ! (in that specific round)

The answer is because 75% on each of two hands gives a very close approximation (exact number is 76%, I think ?) to the SAME variance you get for playing one hand at 100%. Don't believe me ? Sim x million shoes - once playing a single hand and once playing 2 hands @ 75% (both heads up). EV and variance should be just about the same.

This is blackjack 101... I can specifically remember Wong explaining this in a little bit of detail in Professional BJ, I am sure this can be found in any good BJ book.
D.
Click to expand...
Oh yeah. You are right. Splitting to 2 x 75% of max bet equals the same variance but 150% of the EV. I make this play routinely, just had forgotten the math behind it. :rolleyes: I have a large library of Blackjack texts. This shows the need to reread then occassionally.

Actually in my case, my max bet is $300, but I spread to 2 hands of $200 when I can, so I am actually reducing variance because I am only betting 67% of my bet on two hands, while increasing EV.
 
D

Deathangl13

Well-Known Member
kewljason said:
WTF?? :confused: What kind of comment is that? What are you 12 years old? Grow up dude.
Click to expand...

Oh sorry.... :whip: No time for jokes... all business, all business...

I'll stiffen up.... I'm sorry. Kids, stop having fun....
 
B

bj21abc

Well-Known Member
Playing 2, 3 or more hands

However...remember that if you're playing heads up, and you play 2x200 instead of 1x300 you are reducing variance but also reducing your EV by ~ 10%...

If you do have to play on full tables (I get to play heads-up max 5% of the time :() it would be an interesting exercise to see when (how many ploppy hands) it would be worthwhile to play 3 hands, cover notwithstanding. It's not that complicated, but for some reason I can't recall having seen it discussed before.

D.

kewljason said:
Oh yeah. You are right. Splitting to 2 x 75% of max bet equals the same variance but 150% of the EV. I make this play routinely, just had forgotten the math behind it. :rolleyes: I have a large library of Blackjack texts. This shows the need to reread then occassionally.

Actually in my case, my max bet is $300, but I spread to 2 hands of $200 when I can, so I am actually reducing variance because I am only betting 67% of my bet on two hands, while increasing EV.
Click to expand...
 
You must log in or register to reply here.
Top