really two things going on you want to somehow figure out a good encoding scheme but the other part is you want to do really well at this part over here which is a maximum likelihood estimator because that's going to help you ensure encoding scheme is actually good on the data now what if P of X is high entropy if P of X is high entropy that would gain a very long code length which you might not like you might be able to decrease the entropy by considering conditional entropies if you condition X on the context let's say what has come before