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GATE 2024 DA – Question 27

Database Management and Warehousing · Data transformation: normalization, discretization, sampling, compression · 1 mark · Multiple choice

Let the minimum, maximum, mean and standard deviation values for the attribute income of data scientists be ₹46000, ₹170000, ₹96000, and ₹21000, respectively. The z-score normalized income value of ₹106000 is closest to which ONE of the following options?

  1. 0.217
  2. 0.476
  3. 0.623
  4. 2.304

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Correct answer: (B) 0.476

Explanation

The z-score is $\frac{x - \mu}{\sigma} = \frac{106000 - 96000}{21000} = 0.476$. The minimum and maximum values are not needed (they are used for min-max normalisation).