super confused!! what is the probability that the sum of rolling a die is exactly n at any one point in time (assuming we keep on rolling). what is the probability as n goes to infinity? please explain the logic in super-dummy terms please.

Question

anonymous · Answer

Sure.

anonymous · Answer

As n (the number of times it is rolled) approaches infinity, we can expect a more and more 'perfect' answer. Now, how can we calculate the perfect answer? It is the probability of rolling any one number, which is 1/6. Of course if you rolled a dice six times, you might not get every number once as your 'perfect' answer would suggest. You might get two ones and no fives, for example.

However, if you did it 60 times, you might find you get 11 ones, 9 fives, 8 sixs, 12 twos, 10 threes and 10 fours. See how each is closer to our original answer of 1/6?

If you did it 1000 times, then it should be even closer (when simplified) to 1/6.

So if you did it an infinite amount of times, you should get the perfect answer of 1/6.

anonymous · Answer

thanks ElectonicSpark! the idea of infinity and "perfect" sort of makes sense. 
im really sorry if the question was vaguely phrased --- n was actually the *Sum* of n rolls*, so the chance of rolling a 2 total in summ is the chance of rolling a 2 in the first roll, or two 1's successively, which becomes 1/6    +    1/36 as the chance of getting a sum of 2

anonymous · Answer

im having trouble conceptualizing this

anonymous · Answer

Same thing.

Just imagine infinity as a point to which you want to get to. As you get closer and closer you get a better and better answer, but you can never reach infinity, so you can never get your perfect answer.

anonymous · Answer

? alas, my teacher told me it is 2/7 as n --> infinity 
and her reasoning was vague
something like 3.5 being the average added to the sum
??? geez, i wish i were better at math!

anonymous · Answer

but thanks for the suggestions!

anonymous · Answer

Yes, sorry, basically with the addition, comes and extra demonator, so it becomes out of 7. With adding two numbers, the numerator is 2, because you are dealing with two numbers.

anonymous · Answer

thanks!