The slope b₁ of the least squares line represents the:

A) predicted value of Y when X = 0.
B) estimated average change in Y per unit change in X.
C) predicted value of Y.
D) variation around the regression line.

Slope

The rate of change in the variable on the y-axis per unit change in the variable on the x-axis in a coordinate system; it quantifies the steepness of a line.

Least Squares Line

A linear equation that minimizes the sum of the squares of the differences between observed and predicted values.

Regression Line

A line of best fit through a dataset in regression analysis, representing the relationship between independent and dependent variables.