Drawing Box Plots:
- Use a ruler: Draw neat, straight lines
- Equal scale: Use consistent spacing on your number line
- Clear markers: Mark all five values clearly
- Proper proportions: Box and whisker lengths should reflect actual data
- Vertical alignment: Keep everything at the same height
Finding Quartiles:
- Even n: Split data exactly in half, find medians of each half
- Odd n: Exclude the overall median, find medians of each half
- Double-check: Q1 < Median < Q3 always
- Calculator method: Learn your calculator's quartile functions
Interpretation:
- Compare medians: For typical values
- Compare IQRs: For consistency
- Look at skewness: Position of median in box
- Consider context: What do the numbers represent?
This exam tips covers Exam Tips for Box Plots within Box Plots for GCSE Mathematics. Revise Box Plots in Statistics for GCSE Mathematics with 18 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 11 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Practice questions for Box Plots
On a box plot, what does the box (the rectangle) represent?
Two athletics clubs record the 100m sprint times (in seconds) for their members. The five-number summaries are shown below. Club A: Min = 11.2, Q1 = 12.4, Median = 13.1, Q3 = 14.2, Max = 16.5 Club B: Min = 12.0, Q1 = 13.5, Median = 14.8, Q3 = 16.1, Max = 17.3 Compare the distributions of sprint times for the two clubs. You must use the data to support your answer. (3 marks)