14.In TF-IDF what does IDF stand for?  A. Inverse Document Frequency  B. Indented Document Frequency  C. Index Document Frequency  D. Inverse Data Frequency

Answer

In the context of TF-IDF, IDF stands for A. Inverse Document Frequency.

Explanation

The TF-IDF (Term Frequency-Inverse Document Frequency) is a statistical measure used to evaluate the importance of a word in a document relative to a collection of documents or corpus.

1. Term Frequency (TF) measures how frequently a term occurs in a document.
2. Inverse Document Frequency (IDF) measures how important a term is by considering the number of documents in which the term appears. The more documents that contain the term, the lower its IDF score.

The IDF is calculated using the formula:

$\text{IDF}(t) = \log \left( \frac{N}{|\{d: t \in d\}|} \right)$

where:

• $N$ is the total number of documents,
• $|\{d: t \in d\}|$ is the number of documents containing the term $t$.

In this way, the weight of terms that appear frequently in many documents is reduced, highlighting terms that are more unique to specific documents.