Motor Vehicle
in Order to Predict Motor Vehicle Purchases for the U.S.,the

Motor Vehicle
In order to predict motor vehicle purchases for the U.S.,the coefficients of a multiple regression equation were estimated using 25 years of data.The variables were:
y = motor vehicle purchases (billions of dollars)
x₁ = disposable personal income (billions of dollars)
x₂ = U.S.population (millions of persons)
x₃ = automobile installment credit (billions of dollars)
Part of the results using MINITAB was: The regression equation is
$Y = - 61.3 - 0.0022 \times 1 + 0.368 \times 2 + 0.725 \times 3$
$\begin{array} { l l l l } \text { Predictor } & \text { Coef } & \text { Stdev } & \text { t-ratio } \\ \text { Constant } & - 61.28 & 36.96 & - 1.66 \\ \text { X1 } & - 0.00221 & 0.01504 & - 0.15 \\ \text { X2 } & 0.3679 & 0.2001 & 1.84 \\ \text { X3 } & 0.7254 & 0.2115 & 3.43 \end{array}$
Analysis of Variance
$\begin{array} { l c l } \text { SOURCE } & \text { DF } & \text { SS } \\ \text { Regression } & 3 & 32624 \\ \text { Error } & 21 & 591 \\ \text { Total } & 24 & 33215 \end{array}$
-Use the values in the analysis of variance table to compute R² using the values for SST and SSE or SSR.