According to George Barwood, only a small minority of people have the brainpower to properly comprehend the “complex” Jodi Arias murder case and, in turn, conclude that she is innocent.
I think most people have an intuitive sense that it would be highly unlikely that all twelve people selected to sit on a jury would be in the top 1% for intellectual prowess. But what is the probability of just one juror out of twelve being exceptionally smart? If Barwood is correct, then Ms. Arias, if granted a new trial, would need to have at least one of these rare people on the jury to steer the others in the direction of truth – that the state’s case for first-degree murder is not consistent with the evidence and that she is innocent because she acted in self-defense. And along those same lines, an even more important question is: what is the probability that none of the jurors selected will meet Barwood’s criteria for “smart enough”? After all, the vast majority of people are not, by definition, exceptionally smart and it would seem that there is a rather high likelihood that any jury would consist solely of people “not-smart-enough”. As far as I’m aware, Barwood, a self -proclaimed mathematician, hasn’t attempted to answer these mathematical questions which is odd considering that one of the main themes of his advocacy for Ms. Arias is that she was found guilty, not because she is guilty, but because the jury wasn’t intelligent enough to realize that the state’s case was nonsensical. The state’s case is not going to change, that much is clear, so it seems logical from Barwood’s perspective that one of the top strategies to obtain Ms. Arias’ freedom should be to vigorously push for a more intelligent jury. The only way to do that, barring getting a law passed requiring jurors to have genius or near-genius IQs, would be to convince the defense that their top priority during jury selection must be to seat as many intelligent jurors as possible, not an easy task since high intelligence is rare, so the defense must be extremely diligent and determined. But it would be so much more compelling if Barwood had actual numbers to show them first. The binomial distribution can provide the numbers and no complex calculations are required if you use Microsoft Excel because it does the calculating for you. I was curious so I did them.
It’s important to note that selecting a jury is not equivalent to tossing a coin. Coin tossing lends itself perfectly to analysis by the binomial distribution. Jury demographics, less so, but the binomial distribution is still an important and appropriate tool to use for our purposes. It’s more precise to think of it as determining the probabilities of obtaining certain iterations of a jury when the jurors are selected randomly from the jury pool, which is not entirely how jurors are chosen in the real world. Basically, the calculated probabilities are letting us know what the lawyers are up against in their effort to create the jury that they want.
Only about 1% of the population-at-large has an IQ of 135 or greater. According to Barwood, 135 is likely the minimum IQ necessary to be “smart enough”. However, the jury pool does not include everyone in the population. Certainly, people with severe to moderate intellectual deficits are not part of the jury pool. This decreases the overall population from which jurors are selected. Because of this, the likelihood of a person with an IQ of at least 135 serving as a juror cannot be determined by using the 1% parameter since it is based on an accounting of everyone in the population. By using a truncated normal curve that excludes all people with IQs less than 100 (which I think is more than fair), we can determine the probability of a random person having an IQ of at least 135 out of the subpopulation of people with IQs of 100 or greater. That probability is 1.963% and was used in the calculations that make up the chart below:
As you can see, the probability of exactly 0 out of 12 jurors having IQs equal to or greater than 135 is 78.83%. The probability of exactly 1 juror out of 12 having an IQ of at least 135 is 18.94%. And the probability of all 12 jurors having IQs 135 and above is, for all practical purposes, 0%. Not the best odds for Ms. Arias, if Barwood is correct.
But what if it’s even worse than that? Barwood did state that the percentage of people “smart enough” may be as low as 0.01% of the population, which is equivalent to an IQ of 155 or greater. This is the chart for that situation:
With an IQ that rare, is it really any surprise that the probability of exactly 0 jurors out of 12 being “smart enough” is nearly 100%? The defense will have to work awfully hard, using every resource available to them, employing every trick in the book, to even have a chance of finding and impaneling at least one such juror. Or they will have to be extremely lucky.
If Barwood is correct, Ms. Arias is doomed.
I agree with the second part anyway.
😉
Crash-Tested Truths 
To Common Core.
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