This exam tips covers Drawing Histograms: Step-by-Step within Histograms for GCSE Mathematics. Revise Histograms in Statistics for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 10 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Drawing Histograms: Step-by-Step
- Organize Data: Create a frequency table with class intervals
- Calculate Class Widths: Find the width of each interval
- Calculate Frequency Density: Frequency ÷ Class Width for each interval
- Choose Scales: X-axis for class boundaries, Y-axis for frequency density
- Draw Bars: No gaps, height = frequency density, width = class width
- Label Everything: Axes, title, and include units
Common Exam Tips:
- Always use frequency density, not frequency, on the y-axis
- Check class boundaries carefully (inclusive/exclusive)
- No gaps between bars (unlike bar charts)
- Area of each bar equals the frequency
- Use class midpoints for mean estimation
Practice questions for Histograms
A histogram shows the heights (cm) of plants in a garden with the following frequency densities: - 0 =< h < 5: frequency density = 4 - 5 =< h < 15: frequency density = 3 - 15 =< h < 25: frequency density = 6 - 25 =< h < 40: frequency density = 2 What is the modal class?
A histogram is drawn with unequal class widths. A student says: 'I can just use frequency on the y-axis instead of frequency density — the shape of the histogram will look the same.' Is the student correct? Explain your answer.