Ch12.1 Simple Linear Regression The Simple Linear Regression Model There exists parameters such that for any fixed value of x, the dependent variable is related to x through the model equation ε is a random variable (called the random deviation) with E(ε) = 0 and V(ε) = σ2 One can see how a dependent variable is related to an independent variable with a scatter plot. Ch12.1
Ch12.1 Estimating Model Parameters Principle of Least Squares The vertical deviation of the point (xi,yi) from the line y = b0 + b1x is yi – (b0 + b1xi) The sum of squared vertical deviations from the points to the line is: Ch12.2
The error sum of squares, denoted SSE, is and the estimate of σ2 is A computational formula for the SSE, is The total sum of squares, denoted SST, is The coefficient of determination, denoted by r2, is given by Ch12.2
The least-squares (regression) line for the data is given by where and The fitted (predicted) values are obtained by substituting into the equation of the estimated regression line: The residuals are the vertical deviations from the estimated line. Ch12.2