7) The word "good" appears in all 37 Shakespeare plays. Suppose it appears 170 times in the play
"As good as it gets". What is the tf-idf score of "good" and "As good as it gets"?
To calculate the tf-idf (Term Frequency-Inverse Document Frequency) score, we need two values for each term: the term frequency (tf) and the inverse document frequency (idf).
1) Term Frequency (tf):
The term frequency is calculated as the number of times a term appears in a document divided by the total number of terms in that document.
In the play "As good as it gets," the word "good" appears 170 times.
tf("good") = 170 / Total number of terms in "As good as it gets"
2) Inverse Document Frequency (idf):
The inverse document frequency is a measure of how rare a term is across all documents. It is calculated as the logarithm of the total number of documents divided by the number of documents containing the term.
In this case, we have information about the occurrence of the term "good" in all 37 Shakespeare plays. Since it appears in all the plays, the idf would be constant.
idf("good") = log(37 / 37) = log(1) = 0
3) Calculation of tf-idf score:
tf-idf score is obtained by multiplying the term frequency (tf) and the inverse document frequency (idf).
tf-idf("good", "As good as it gets") = tf("good") * idf("good") = 170 * 0 = 0
Therefore, the tf-idf score of "good" and "As good as it gets" is 0.