📈 Module 2: Fitting and Interpreting Simple Regression

Understanding the regression equation and what it tells you

Learning Objectives

Understand the regression equation: Y = a + bX
Interpret the slope and intercept correctly
Understand R² and what it measures
Make predictions using the regression equation

The Regression Equation

Y = a + bX

Where:

Y = Predicted value of the outcome
X = Value of the predictor
a = Intercept (Y when X = 0)
b = Slope (change in Y per 1-unit change in X)

Demo 1: Understanding Slope and Intercept

Adjust the slope and intercept to see how they affect the regression line.

Intercept: 50

Slope: 5

Demo 2: Understanding R²

R² tells you what proportion of variance in Y is explained by X.

Key Takeaways

Remember:

The slope tells you how much Y changes per unit of X
The intercept is Y when X = 0
R² tells you percent of variance explained (0 to 1)
Use the equation to make predictions