9.1 Linear Regression 9.1.1 Review of the basics The lm function in R constructs—as its name implies—a linear model from data. Recall that a linear model is of the form Y = β0+β1X1+...+βnXn Y = β 0 + ...

Example: If we have a regression equation \ (Sales = \beta_0 + \beta_1 Advertising\), then we can use \ (\beta_1\) to better understand the impact of our spending on advertising on sales. Obviously, ...