Central limit theorem

1. Oct 5, 2009

PullMeOut

1. The problem statement, all variables and given/known data
consider an experiment with 2 possible outcomes, 1 and 0, with a priori probabilities p and
1-p. we would like to find out the average (expected) deviation after N trials, of the relative frequency of the "1"s, N1/N
Use the central limit theorem to find expected deviation.

2. Relevant equations

N1=$$\sum$$$$^{N}_{i=1}$$ ni , where ni is the outcome of the ith trial
3. The attempt at a solution

I know expected deviation of N1 is the square root of its variance.
and variance is:
$$\sigma$$$$^{2}$$=<x$$^{2}$$> - <x>$$^{2}$$

<x>=$$\sum$$$$^{N}_{i=1}$$pi xi

but i have to use central limit theorem
$$\lim_{N \rightarrow inf } \left(N1/N)$$

and i'm lost , the question looks so easy but i have no idea what to do?