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📐 Mathematics  ·  Statistics  ·  JEE

The standard deviation of a data set is the ___ of its variance:

Answer: the square root.

  • A the square root
  • B the square
  • C the reciprocal
  • D double the value

Correct answer: A. the square root

Explanation: Standard deviation = √(variance).

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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