Blackjack Patterns

[jquad]

Hello everyone,

This is my first post on this forum. I have just finished a blog post about questions I have on patters I have seen over the years. Please take a look at it and let me know of you have seen any of these patterns or any others. You can find the blog at

[ADMIN: Link to very poor source removed. Adding it back will result in a ban.]

Thanks in advance for your replies

[Chip Hoarder]

Anyone who has played for any significant length of time will have noticed many such patterns. To deny their existence is to deny human nature. However, enlightenment consists in recognizing that these patterns are a product of our own minds, and not of anything external to them.

[bigplayer]

The cycle for BJ's is roughly 1 per 21 hands...with lots of variance. The chances of hitting 0 BJ's in 21 rounds is 36.78%, of hitting 1 BJ in 21 rounds is 36.78%, of hitting 2 is 8.31%. Of hitting 10 in 21 rounds is a 1 in 70,000,000 shot. And of course all of those possibilities the blackjacks are randomly distributed in any number of combinations creating all sorts of meaningless patterns.

[Roswell Crash Survivor]

That source is pure plopliness.

[Nyne]

The cycle for BJ's is roughly 1 per 21 hands...with lots of variance. The chances of hitting 0 BJ's in 21 rounds is 36.78%, of hitting 1 BJ in 21 rounds is 36.78%, of hitting 2 or more is 8.31%. Of hitting 10 in 21 rounds is a 1 in 10,000,000 shot. And of course all of those possibilities the blackjacks are randomly distributed in any number of combinations creating all sorts of meaningless patterns.

I agree 100% with your point, but the math isn't quite right.

I agree that a BJ happens about once per 21 hands, but that means the chances of hitting none in 21 rounds is 35.89%. Hitting 1 BJ in 21 rounds is 37.69%, and 2 or more is 26.42%. 10 or more in 21 rounds is 1 in 76,872,198.

[bigplayer]

I agree 100% with your point, but the math isn't quite right.

I agree that a BJ happens about once per 21 hands, but that means the chances of hitting none in 21 rounds is 35.89%. Hitting 1 BJ in 21 rounds is 37.69%, and 2 or more is 26.42%. 10 or more in 21 rounds is 1 in 76,872,198.

Thanks for the correction...I had the chances of hitting exactly two is 8.31% according to my POISSON Excel Spreadsheet (don't know why I wrote "or more"). I probably didn't have enough decimal places in my estimate of prob of 10 out of 21 rounds to get the exact number so I just counted decimal places out to the 10 millions.

[Nyne]

I had the chances of hitting exactly two is 8.31% according to my POISSON Excel Spreadsheet

I've got 18.84% for exactly 2 blackjacks in 21 rounds, using the following formula:

(1/21)^2*(20/21)^19*combin(21,2)

Is this formula incorrect?

[bigplayer]

I don't know where I got that number....I get 18.39% so we are pretty close.

One Variable
1	User specify the mean
1.00
x	f	cum	1-cum
0	36.787944%	36.7879441%	63.2120559%
1	36.787944%	73.5758882%	26.4241118%
2	18.393972%	91.9698603%	8.0301397%
3	6.131324%	98.1011843%	1.8988157%
4	1.532831%	99.6340153%	0.3659847%
5	0.306566%	99.9405815%	0.0594185%
6	0.051094%	99.9916759%	0.0083241%
7	0.007299%	99.9989751%	0.0010249%
8	0.000912%	99.9998875%	0.0001125%
9	0.000101%	99.9999889%	0.0000111%
10	0.000010%	99.9999990%	0.0000010%