(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Suppose a particle moves along the x-axis beginning at 0. It moves one integer step to the left or right with equal probability. What is the pdf of its position after four steps?

2. Relevant equations

Binomial distribution

##P(k) = {{n}\choose{k}} p^k (1-p)^{n-k}##

3. The attempt at a solution

In this case, ##p=0.5## and ##n=4##, so

##P(k) = {{4}\choose{k}}\frac{1}{16}##

But this is intuitively wrong, as ##P(0)## should be maximum, but here ##P(0) = \frac{1}{16}##. What am I missing here? Thank you.

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# Homework Help: Random Walk - 1 dimension

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