"normanstrong" wrote in message
news:vilHb.56707$VB2.101814@attbi_s51...

"Scott Gardner" wrote in message
...
Does anyone know the general equation that tells you how many trials
a
subject must complete successfully to achieve a desired certainty
that
the results weren't from guessing?

In other words, for "N" trials, what number "M" of them must the
subject complete successfully to be "X" percent sure the results
weren't from guessing?

If the probability of guessing right in a single trial is 50%, and
there are 10 trials, the chance of getting all of them right is 1 in
1024 (1/2^10).

If you allow for 1 mistake, your chances are improved about 10 times
(1.1%)

2 mistakes improve the odds another 5 times (5.5%) This is as far as
I would go.

Another interesting question is: How many times do you have to do
this test before you have an even up chance of correctly guessing 8
out of 10 tries? The answer is 12 times. IOW, if 12 people try to
get 8 out of 10 right, half the time at least one will succeed--by
luck alone.

you are ready to dive into a cesspool of fallacy.
let me blow the whistle. GO!




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