Wednesday, March 23, 2005

One million dollar Paranormal challenge, what are chances of winning?

JREF offers a one-million-dollar prize:

Randi's challenge consists of checking to see whether a psychic can really do what he claims to be able to do. The psychic sets the requirements of the test in cooperation with the JREF. Randi makes all conditions as favorable as possible to the psychic.

Now it's up to the psychic to say exactly what he can do. If he can consistently predict accurately in a number of trials with the same results in carefully controlled experiments, all he has to do is agree with the JREF to how many trials they both agree are enough to establish significance.

If he says he will divert a specific number of trials with the same result, he may not come back and say he was successful because only one trial went wright. If he claims he can do this "thing" a predetermined numbers of time, he can't later claim he succeeded because he only did it once or twice.

If he can really do what he claims, the probability of his success is near 100%.

But what if the psychic isn't "psychic", then what are chance of winning?

On any given attempt, the psychic can either predict accurately or cannot predict accurately. The probability may be 1/2 on each trial, it can be either wright or wrong, and for 10 trials, the probability of getting each one right is one in 1024 (210). You have a one in 512 (29) chance of guessing right on 9 out of 10 trials. So it depend on how many trials the psychic and JREF agree on. And it has to be done at least twice, both in a preliminary trial and if he pass through, then in the official trial.

The person who has paranormal, supernatural or occult power abilities have a 100% chance of winning. If not, he has 100% chance of losing (nearly). If one really has paranormal abilities, then the probability is essentially 100% that he would claim the prize, barring having an "off" day.

If the person does not have paranormal abilities, then the probability is essentially zero that he would do well enough to claim the prize, barring a statistically unlikely series of lucky guesses.

To my knowledge, no one in the history of humanity has ever proven that he has paranormal abilities.

Usefull links:
Application for Status of Claimant
The JREF Million Dollar Paranormal Challenge "FAQ"
JREF Forums: Million Dollar Challenge
Search james Randi "million to one
Are the Randi Tests Fair?

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