tf-idf: a weighting scheme used by search engines in ranking a document's relevance given a user query.
idf : indicative of the importance of a word
tf: how frequent the word is in a document.
idf (w) ∝ log ( No. of docs in the corpus / No. of docs containing that word w)
tf(w) = No. of instances of w in the doc / max instances of any word in the doc
Normalized weight or tf/idf ranking = tf(w) X idf(w)
Ramya
