11.85 Casper Jensen, director of energy affairs at the Ministry of Economic Affairs, wants to know whether mindset or taxes are the better instrument to stimulate the adoption of renewable energy resources to tackle climate change. He asks you to prepare an analysis investigating the relationship between the change in the renewable energy share and the percentage of environmentally minded households on the one hand and the energy tax rate for households in 2004 on the other hand. Data for this study are in the data file Renewable Energy.

a. Prepare graphical plots and regression analyses to determine the relationships between the change in the renewable energy share and the percent of environmentally minded households and the energy tax rate for households in 2004. Compute 95% confidence intervals for the slope coefficients in each regression equation.

b. What is the effect of a 1 percentage point lower energy tax rate on the change in the renewable energy share?

c. For the environment-minded regression, what is the 95% confidence interval for the change in the renewable energy share at the mean percent of environmentally minded households? And at 10 percentage points above this mean?