NO.PZ202108310100000102
问题如下：
Which of Bector’s statements regarding TF, IDF, and TF–IDF is correct?
选项：
A.Statement 1
Statement 2
Statement 3
解释：
C is correct.
Statement 3 is correct. TF–IDF values vary by the number of documents in the dataset, and therefore, the model performance can vary when applied to a dataset with just a few documents.
Statement 1 is incorrect because IDF is calculated as the log of the inverse, or reciprocal, of the document frequency measure.
Statement 2 is incorrect because TF at the sentence (not collection) level is multiplied by IDF to calculate TF–IDF.
A is incorrect because Statement 1 is incorrect. IDF is calculated as the log of the inverse, or reciprocal, of the document frequency (DF) measure.
B is incorrect because Statement 2 is incorrect. TF at the sentence (not collection) level is multiplied by IDF to calculate TF–IDF.
statment3的意思是？为什么选3，在课件里哪里提到了？
