Which of the following is not included when analyzing word choice?
pronunciation
vocabulary
level of formality
meaning of the words

Word choice, also known as diction, is the words a writer chooses to use in their writing based on a number of components.

It wouldn't make sense for a writer to not know the meaning of a word and still use it in their writing, so "meaning of words," is included.

Vocabulary is included as well. Diction and vocabulary are pretty much the same thing. 

Level of formality is included because you can tell if a writing is formal or informal based on the word choices the writer uses. For example, if a writer writes  "There are a lot of things to do in New York City," that would be informal since there are better words to use than "a lot" and "things." To make it formal, it could be "There are numerous activities to do in New York City." 

Therefore, when analyzing word choice the "pronunciation," is not included.