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All the students of a class performed poorly in Mathematics. The teacher decided to give grace marks of 10 to each of the students. Which of the following statistical measures will not change even after the grace marks were given ?
- mean
- median
- mode
- variance
Correct answer: variance
Solution
Adding 10 to every value shifts mean, median, and mode each by 10, but the spread about the mean is unchanged, so variance stays the same.
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