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Edited on Sat Dec-04-04 11:27 AM by TruthIsAll
I posted yesterday asking that mathematicians confirm or refute my calculation of the probability that AT LEAST 16 out of 51 states would move beyond the MOE in favor of Bush. Well, they refuted it.
Sort of.
I originally calculated the odds at 1 in 4.5 BILLION. That was too conservative. On further analysis, I calculated the odds as 1 in 200 TRILLION. But I was still off.
Thanks to MathGuy and JFERN for checking (and fixing) my calculation of the odds.
MathGuy calculates: 1 in 13.5 TRILLION JFERN has it as: 1 in 14.5 TRILLION
So which is mathematically correct? They BOTH seem right to me. Maybe we should just split the difference and say: 1 in 14 TRILLION.
For the sake of mathematical purity (and the trolls), we had better get to the bottom of this discrepancy. Hehehehehehe.
Here is my original calculation for the odds that 16 out of 51 states would move beyond the MOE in favor of Bush, using the Binomial Distribution, with .025 as the probability that a given state would move beyond the MOE to Bush:
The Excel formula for P: P = 1 – BINOMDIST ( 16, 51, 0.025, TRUE) P = 0.000000000000004996 The odds: 1 / P or 1 out of 200.159 TRILLION (that the deviations could have occurred due to chance).
MathGuy made this input parameter change (16 to 15) to the Binomial function: P = 1-BINOMDIST (15, 51, 0.025, TRUE) The odds: 1 in 13.5 TRILLION.
Then JFERN offered this elegant answer: 51 choose 16 * 0.025^16 * 0.975^35 The odds: 1 in 14.5 TRILLION.
If someone can resolve the 1 TRILLION discrepancy, please do so.
Here is my confirmation of JFERN’s calculation: "51 choose 16" means the number of combinations of 51 states taken 16 at a time.
I used the Excel combinatorial function to calculate this:
COMBIN (number, number_chosen) This function returns the number of combinations for a given number of items.
COMBIN is used to determine the total possible number of groups for a given number of items, where: -number is the number of items. -number_chosen is the number of items in each combination.
Here is the calculation sequence:
1. Number of combinations of 51 states taken 16 at a time: C = COMBIN(51,16) = 7.17452E+12
2. The probabilties (16 beyond MOE, 35 within) for each combination: JP = 0.025^16 * 0.975^35 = 9.59846E-27
3. Sum the total probabilities of all combinations: P = C*JP = 0.0000000000000688643 = 6.88644E-14
4. Calculate the odds: 1 / P
***** 1 in 14,521,300,254,785 ******
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