Study notes

Statistics & Probability

Quartiles, spread (range, IQR, standard deviation), cumulative frequency and box-and-whisker plots, and probability of combined events.

What this topic covers

  • Quartiles split ordered data into four equal parts
  • Range and interquartile range (IQR) measure spread
  • Standard deviation measures spread from the mean
  • A cumulative frequency diagram lets you read off the median and quartiles
  • A box-and-whisker plot displays the five-number summary
  • Combined events use the addition and multiplication rules

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