Hi Andrew,

Of course, you're right :) I asked John specifically to show him, that his theory doesn't work at any time...

>Nadya,
>
>The answer to your question is
>
>p = (2^n - 1)/(2^n)
>
>because any one even number (i assume you're using integers) will make the product even.
>
>More simply, it's
>
>p = 1 - (0.5)^n
>
>Because the probability of picking all odd numbers is (0.5)^n, and the probability of getting an even product is 1 - (probability of picking all odd numbers)
>
>What John hasn't taken into account in his formula is that it only works if each of the outcomes is equally likely (like rolling dice or whatever [except in Vegas :)]). If the outcomes have a different likelyhood, then you need to weight each outcome in proportion.
>
>Hence, on some days, the chance of precipitation is > 0.5 and on some days it is less. There are sophisticated models used to estimate the likelyhood of weather (none of which work very well in my experience <g>) and so the forecasters think they can do better than just p=0.5 as John would have.
>
>Cheers,
>
>Andrew
>
>>Hi John,
>>>>>>
>>>> May I ask you a very simple question, but you should answer in just one second:
>>>>What's the probability, that the product of 2 random numbers in even? Now 3 numbers, now 4...
>>>
>>>The same formula should apply - possible outcomes over population.
>>
>>So, you answer is ????????
>>And now think ...