UNIT OVERVIEW

This unit teaches you how to find patterns in data involving two variables. You will learn to answer questions like: "Does studying more hours improve your marks?" or "Is there a link between advertising spending and sales?"

In Grade 11, you described single-variable data using measures like mean and standard deviation. Now you will work with bivariate data — data with two related variables.

What You Will Learn

• How to identify symmetric and skewed data distributions
• How to draw and interpret scatter plots
• How to calculate the least squares regression line (line of best fit)
• How to use regression equations for prediction (interpolation and extrapolation)
• How to calculate and interpret the correlation coefficient ($r$)
• How to comment meaningfully on data trends
• How to recognise limitations of regression analysis

Real-Life Applications

• Agriculture: Farmers predict crop yields from rainfall data
• Healthcare: Researchers study links between risk factors and diseases
• Business: Retailers predict sales from advertising spend
• Sports: Coaches analyse which factors predict match performance
• Education: Universities study links between matric results and university success

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