What is it
Regression finds the equation of the line of best fit through a data set, allowing predictions to be made for values of one variable based on another, using the least squares method.
Why it matters
Regression is the statistical technique behind predictive modelling in virtually every field — from forecasting sales to estimating exam grades from mock results — making it one of the most practically applied topics in the whole syllabus.
Exam tip
Only use a regression line to predict within the range of the original data (interpolation) — extrapolating far beyond the data range is a specific, commonly tested error that examiners expect you to identify and avoid.
Related topics
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