Readability measures are used to score the reading difficulty of a text, for the purposes of selecting texts of appropriate difficulty for language learners. Let us define _wto be the average number of letters per word, and _sto be the average number of words per sentence, in a given text. The Automated Readability Index (ARI) of the text is defined to be:4.71w+ 0.5s- 21.43.

Compute the ARI score forany 5 categoriesof the Brown Corpus (nltk.corpus.brown.categories()). Make use of the fact thatnltk.corpus.brown.words()produces a sequence of words, whilenltk.corpus.brown.sents()produces a sequence of sentences.