[[Don Schlesinger]] EOR Tables in general

**Math Demon** · 09-13-2013, 01:31 PM

Hello Don.

On page 498 of BJA3, Checking the Quality of EOR Tables, you stated:

"An EORs table is supposedly a fair and accurate one if: Sum Ei * Pi = 0; that is, the EOR of a single rank times its probability of being drawn, summed over the thirteen different values should be zero."

Obviously this applies to Blackjack, and all tables I've seen generated by Griffin, Cacarulo and you bear this out.

My question revolves a slightly different game. In Spanish 21, all 10s are removed. I am assuming that the "Sum Ei * Pi" for the remaining 12 ranks should still be zero. Is this correct?

However, in Katrina Walker's SP21 book, the sum for SP21 H17 is -0.09. I had also received EORs for SP21 S17 in which totals +0.24. Can these figures be correct?
__

Table 5.1 in Katarina Walker's book on Spanish 21 H17

rank.........2...... 3...... 4...... 5...... 6...... 7...... 8...... 9...... J...... Q...... K...... A......tot
SP21 H17.. +0.29.. +0.40.. +0.56.. +0.65.. +0.40.. +0.04.. -0.21.. -0.17.. -0.44.. -0.44.. -0.44.. -0.73.. -0.09

Thanks very much,
Math Demon

P.S. Norm, can the EORs in Spanish 21 be generated using CVData?

**Three** · 09-13-2013, 02:47 PM

Both Sp21 numbers you are referring to are from Kat's book.

**Math Demon** · 09-13-2013, 03:53 PM

Originally Posted by Tthree

Both Sp21 numbers you are referring to are from Kat's book.

Hello Tthree. The SP21 (H17) is on Table 5.1 in Kat's book. I can find no reference for EORs for the SP21 S17 in it. Can you tell me which table or page it's located?

Thanks,
MD

**DSchles** · 09-13-2013, 04:57 PM

"However, in Kat[a]rina Walker's SP21 book, the sum for SP21 H17 is -0.09. I had also received EORs for SP21 S17 in which totals +0.24. Can these figures be correct?"

You didn't divide by the probabilities; i.e., you don't just sum the EORs. You need to divide, in this case, by 12. So, if Kat's values are "off," they are so by a lot less than you may have at first imagined, as -0.09/12 = -0.0075, and +0.24/12 = +0.02.

On p. 498, which you allude to, I state that values < 0.01 are generally considered acceptable. So, the first of your numbers meets that criterion, while the second isn't very good.

Don

**Three** · 09-13-2013, 05:17 PM

Originally Posted by Math Demon

Hello Tthree. The SP21 (H17) is on Table 5.1 in Kat's book. I can find no reference for EORs for the SP21 S17 in it.

I guess I was mistaken.

**Three** · 09-13-2013, 05:23 PM

Originally Posted by DSchles

So, if Kat's values are "off," they are so by a lot less than you may have at first imagined, as -0.09/12 = -0.0075, and +0.24/12 = +0.02.

On p. 498, which you allude to, I state that values < 0.01 are generally considered acceptable. So, the first of your numbers meets that criterion, while the second isn't very good.

Don, do you have a better set of EORs for SP21 S17?