Refrigerator prices are affected by characteristics such as whether or not the refrigerator is on sale, whether or not it is listed as a Sub-Zero brand, the number of doors (one door or two doors), and the placement of the freezer compartment (top, side, or bottom). The table below shows the regression output from a regression model using the natural log of price as the dependent variable. The model was developed by the Bureau of Labor Statistics.
(a) Write the regression model, being careful to exclude the base indicator variable.
(b) Find the p-value for each coefficient, using 319 degrees of freedom. Using an α = .01, which predictor variable(s) are not significant predictors?
(c) By how much does the natural log of refrigerator price decrease from a two-door, side freezer model to a two-door, top freezer model?
(d) Which model demands a higher price: the side freezer or the one door with freezer model?

Variable Coefficient Standard Error t Statistic 41.923 -3.134 7.660 12.999 0.576 5.484092 ntercept Sale price Sub-Zero brand Total capacity (in cubic ft) Two-door freezer on bottom Two-door side freezer Two-door freezer on top One door with freezer One door no freezer 0.13081309 0.02338826 0.14615699 0.00535103 0.0808569 -0.0733 1.11962 0.06956 0.046569 Base -0.343246 -0.709558 -0.881981 0.03595873 0.13097047 0.14913992 -9.546 -5.418 -5.914