Overview
This lesson covers the different types of graphs used in AS Level Psychology, focusing on bar charts, histograms, and scatter graphs, their features, and how to interpret them.
Types of Graphs
Bar Charts
- Bar charts are used to display discrete data.
- The x-axis displays the independent variable; the y-axis shows the dependent variable.
- Bars must be of equal width and equally spaced apart.
Histograms
- Histograms represent continuous data.
- Bars are touching (no gaps) and may not always be equally spaced.
- The x-axis is the independent variable and the y-axis is the dependent variable.
Scatter Graphs
- Scatter graphs are used to show correlational data.
- Each point represents a pair of values for two variables.
- A line of best fit can indicate the type of correlation: positive, negative, or none.
Understanding Axes
- The x-axis (horizontal) typically represents the independent variable.
- The y-axis (vertical) typically represents the dependent variable.
Key Terms & Definitions
- Bar Chart — A graph for discrete data with separated, equally spaced bars.
- Histogram — A graph for continuous data with touching bars.
- Scatter Graph — A graph showing relationships (correlations) between two variables.
- Line of Best Fit — A straight line drawn through scatter plot points to show correlation direction.
- Discrete Data — Data with separate, distinct values.
- Continuous Data — Data that can take any value within a range.
- Independent Variable — The variable manipulated or categorized (on the x-axis).
- Dependent Variable — The variable measured or counted (on the y-axis).
Action Items / Next Steps
- Attempt the provided graph questions without notes, then check answers.
- Review this lesson or previous videos if questions were incorrect.
- Complete the mock test on research methods available on the course website.
- Prepare for the next lesson on the multistore memory model.