Page 20 shows how to calculate total SD when backcounting. I am assuming from your sim that it is showing the frequency of hands played rather than total hands including hands observed. If I am wrong I don't know what is going on. If your data is play-all data, then I am wrong.
Yes, I understand that page 20 shows a back counting example. Can I use the same technique on page 20 for a non-back counting example? I would assume that I would just divide the variance by a total frequency of 1.00 instead of the hands played decimal in back counting.
Yes. That works. I assume you used back counting because you didn't seem to make any other mistakes to explain the discrepancy. If you aren't playing all the total frequency should not be 1.00. If you are playing all I didn't spot another mistake. But when that is confirmed I will look again.
Hmm, that didn't work. Just to be sure. SD total = $82.48 / $32.60 = 2.53 (that's SD per round divided by average bet)
I ran the "sum of the product of bet*Freq*variance divided by average bet then square root" and came up with SD = 1.159. Hmm
SD math.jpg
The bet size has to be squared. What is so hard about following EXACTLY what was done on page 20? Why does everyone have to reinvent the wheel and make 82 mistakes in the process. Just do what I did, for crying out loud. This isn't rocket science.Originally Posted by MercySakesAlive
You don't have to KNOW anything. Just copy what was done.
Don
Thanks. Got it working now. Here's the formula for SD total for anyone who may be interested.
SD formula.jpg
LOOK at this:
https://www.dropbox.com/s/vdfrlc7qj1lfub6/Z%20Scores.gif?dl=0
This simple graphic is helpful in seeing the relationship between
Standard Deviation, Z-Scores, etc. etc.
Understanding "measures of central tendencies" is invaluable.
Last edited by ZenMaster_Flash; 05-23-2018 at 08:16 AM.
I ran the formula once on a calculator and got the right answer. Thanks for catching the frequency mistake. Perhaps I made a mistake when I did it but I don't think so.
Total Variance = (($5^2*0.8005*1.161^2) + ($60^2*0.0807*1.153^2) + ($200^2*.1188*1.160^2))/($32.6^2*1.00)
= ($$25*1.0790107+ $$3600*0.1072833 + $$40000*0.1598572)/$$1062.76
=($$26.975267 + $$386.21988 + $$6,394.288)/$$1,062.76 = 6,807.4831/1,062.76
= 6.4054754
Total SD = SQRT(Total Variance) = SQRT(6.4054754) = 2.530904
Now double checked on a calculator with the math to be reviewed by all.
I don't see how not dividing by the SQRT(1062.76) would be right, unless you used bets expressed as a multiple of average bet instead of dollars. If you did the latter the division by average bet squared would be dividing by 1, which would drop out of the equation. Of course expressing a bet in any unit would do the same thing. Without adjusting for monetary units of average bet variance would be in dollars and need to be divided by average bet squared or divide the SD calculated by average bet to get the variance that would produce the SD of 2.53 units that the OP is looking for.
Last edited by Three; 05-23-2018 at 08:33 AM.
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