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GATE 2026 DA – Question 47

Machine Learning · Supervised learning: classification · 2 marks · Multiple select

Consider that 20 stories of Author X and 10 stories of Author Y were kept together without mentioning the names of the authors. A classifier was then asked to predict the author (X or Y) of each of these stories. Let, out of X's stories, 6 were classified as that of Y. On the other hand, out of Y's stories, 2 were classified as that of X.

Considering X and Y as two classes, which of the following statements is/are true?

  1. Accuracy of the classifier is 11/15.
  2. Precision of Class X is higher than the Precision of Class Y.
  3. Recall of Class X is higher than the Recall of Class Y.
  4. Accuracy of the classifier is 14/15.

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Show answer and explanation

Correct answer: (A) Accuracy of the classifier is 11/15.; (B) Precision of Class X is higher than the Precision of Class Y.

Explanation

Out of 20 stories of X, 14 are correct and 6 are wrong, and out of 10 stories of Y, 8 are correct and 2 are wrong. The accuracy is $\frac{14 + 8}{30} = \frac{11}{15}$ (A is true, D is false). The classifier says X for $14 + 2 = 16$ stories, so the precision of X is $\frac{14}{16} = 0.875$, and it says Y for $8 + 6 = 14$ stories, so the precision of Y is $\frac{8}{14} = 0.571$. The precision of X is higher (B is true). The recall of X is $\frac{14}{20} = 0.7$ and the recall of Y is $\frac{8}{10} = 0.8$, so the recall of X is lower (C is false).