|Posted: January 15, 2009, 8:12 pm - IP Logged|
90 draws without a 4 in the front, 58 without a 0 in the back!!!
what are the chances??????? read below:: I asked a PHD in math:::::
As you wrote to Dr. Math
On 01/15/2009 at 10:27:04 (Eastern Time),
>What is the probability in a random draw of 10 digits 0-9 that 0ne of
>the #'s doesn't get picked for 90 draws?
>I know the probability of any draw is 10% scientifically, however at
>what point does this change? How is it possible that a certain # does
>not show up for that many draws?
>There has got to be some point that it is mathmatically impossible.
Thanks for writing to Dr. Math.
It never becomes impossible. It can, however, become very unlikely.
That's the thing about probability. Highly unlikely doesn't mean impossible.
The probability that a certain number does not show up in a single draw is 0.9 (90%).
So, the probability it doesn't get drawn 90 times in a row is 0.9^90,
or: 0.000076 (0.0076%).
This is unlikely but not impossible. For reference, this is higher than the probability of getting hit by lightning in the next year. And much higher than the probability of hitting a lottery jackpot.
Even if you were to specify 1000000 draws in a row, the probability goes down, but it never becomes impossible.
- Doctor Roy, The Math Forum
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