Weakly typical sequence
= Weakly typical sequence
For an <IID random variable> source with <probability mass function> $p$, a word $x^n$ is weakly typical when $|-(1/n)\log_2p(x^n)-H(X)|\leq\varepsilon$. It has probability on the scale $2^{-nH(X)}$. The <weak law of large numbers> makes the <typical set> probable, but does not make every word in it representative: for a uniform source every possible word is weakly typical.