S W 318 Lecture Notes - Lecture 12: Scatter Plot, Covariance, Ordinary Least Squares
Document Summary
Scatter diagram (scatterplot) a visual method used to display a relationship between two interval-ratio variables. Typically, the independent variable is placed on the x-axis (horizontal axis), while the dependent variable is places on the y-axis (vertical axis) Linear relationship a relationship between two interval-ration variables in which the observations displayed in a scatter diagram can be approximated with a straight line. Deterministic (perfect) linear relationship a relationship between two interval-ration variable in which all the observations fall along a straight line. The line provides a predicted value of y (the vertical axis) for any value of x (the horizontal axis. ) Y-intercept (a) the point where the regression line crosses the y-axis, or the value of y when x=0. Slope (b) the change in variable y (the dependent variable) with a unit of change in x (the independent variable. ) You want to draw a line that predicts the best results with the least error.
