Sample each point with flipping coin, what is the average?

Question

I need to give some measure concentration for the following problem. Let $x_1,x_2\cdots,x_n$ be $n$ points and for each $i\in [n]$, $x_i\in [a,b]$, suppose now for each $x_i$, we sample it with the probability $\frac{1}{2}$, what is the probability for the error of the average of the sampling points and $\frac{1}{n}\sum_{i=1}^{n}x_i$ is less than some $\epsilon$. Do we have something the same as Hoeffdings inequality?