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📐 Mathematics  ·  Statistics  ·  JEE

For a data set with standard deviation 5 and mean 25, the coefficient of variation is:

Answer: 20%.

  • A 5%
  • B 20%
  • C 25%
  • D 0.2%

Correct answer: B. 20%

Explanation: CV = (SD/mean)·100 = (5/25)·100 = 20%.

Normal Distribution: the 68-95-99.7 Rule68% within ±1σ95% within ±2σmean=median=mode (centre)

In a perfectly normal (bell-shaped) distribution, mean, median, and mode all coincide at the centre; about 68% of data falls within 1 standard deviation of the mean, 95% within 2, and 99.7% within 3 - the empirical rule used to judge how typical or extreme a value is.

Concept context

Mean, median, mode, standard deviation, and data interpretation

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