Box Plot
A graphical display consisting of a rectangular box showing Q₁, median, and Q₃, with lines (whiskers) extending to show the range, and points marking outliers. Outliers are identified using the 1.5×IQR rule.
Real World
The NHS uses box plots to compare hospital waiting times across regions, instantly revealing that London trusts have a wider spread and more extreme outliers than rural areas.
Exam Focus
Always label Q1, median, Q3, and outliers explicitly — unlabelled box plots lose marks even if drawn correctly.
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