Interpretation and Display of Quantitative Data (OCR GCSE Psychology): Revision Note

Frequency tables

• Quantitative data can be represented visually using tables, charts, and graphs

  • These methods help researchers to summarise, compare, and interpret data quickly and effectively

• A frequency table shows how often each score, behaviour, or event occurs, e.g.

  • the number of times litter is dropped

  • the number of goals scored by each player in one season

  • the frequency of marks achieved by students on a maths test out of 10

• From this data, we can calculate the following:

  • Mode: 4 (most frequent score)

  • Median: 5 (middle value)

  • Mean: (1×1 + 2×3 + 3×11 + 4×20 + 5×8) ÷ 43 = 3.7

  • Range: 4

Histograms

• A histogram is used to display continuous data

  • The x-axis shows score intervals or categories

  • The y-axis shows frequency

  • Bars touch each other, showing that the data is continuous

• Histograms are useful when scores cover a wide range or need to be grouped into intervals

  • E.g. showing how many participants of different ages took part in a study

Bar charts

• A bar chart is used for categorical data (discrete data that falls into separate groups)

  • The x-axis shows categories (e.g. “Visual”, “Auditory”, “Semantic”)

  • The y-axis shows frequency or average scores

  • Bars have gaps between them to show separate categories

• Bar charts are useful for comparing conditions in experiments or categories in surveys

Pie charts

• A pie chart presents data as proportions of a whole

  • Each category is represented by a slice, and the size of the slice reflects its frequency or percentage

  • Pie charts make it easy to compare categories at a glance

• Pie charts are used to represent categorical data, such as the average number of words recalled in three memory conditions

Line graphs

• A line graph is used to show changes or trends in quantitative data

  • The x-axis represents time or a continuous variable

  • The y-axis represents scores, frequencies, or percentages

  • Points are plotted and then joined by lines to show trends clearly

• Line graphs are ideal for showing progress, improvement, or change — e.g. memory recall scores over several trials

Scattergrams

• A scattergram (or scatter diagram) is used to show relationships between two variables (co-variables)

  • One variable is plotted on the x-axis, the other on the y-axis

  • Each point represents one participant’s pair of scores

  • The pattern of points shows whether the relationship is positive, negative, or no correlation

• Scattergrams are often used in correlational research to explore associations (e.g. hours of sleep and stress levels)