Visualising Data: Charts, Graphs, and Plots

1. Bar Charts

• Shows categorical data

• Height of bars shows frequency

• Equal gaps between bars

• Must have:

  • Title

  • Labeled axes

  • Scale on frequency axis

  • Equal width bars

2. Line Graphs

• Shows changes over time

• Points connected by lines

• Good for trends

• Must have:

  • Title

  • Labeled axes

  • Suitable scale

  • Points correctly plotted

3. Pie Charts

• Shows parts of a whole

• Total = 360°

• Calculate: (Value ÷ Total) × 360°

• Must have:

  • Title

  • Labels

  • No gaps between sectors

4. Scatter Graphs

• Shows relationship between two variables

• Look for patterns:

  • Positive correlation

  • Negative correlation

  • No correlation

• Can draw line of best fit

5. Histograms

• For continuous data

• No gaps between bars

• Area represents frequency

• Used for grouped data

• Must have equal class widths

Simple Rules to Remember:

• Always label axes

• Use a ruler for straight lines

• Include a title

• Choose suitable scales

• Plot points accurately

• Show working out for pie chart angles

Common Exam Questions Ask You To:

• Choose appropriate chart type

• Draw and label charts

• Interpret patterns

• Spot relationships

• Calculate angles for pie charts

• Draw line of best fit