These data give the gross domestic product (a measure of the size of a national economy, in billions of dollars) and the amount of CO2 (carbon dioxide, in millions of tons) released into the atmosphere in 140 countries in 2010.
(a) Graph the amount of CO2 versus GDP for these countries. Which countries are the three most prominent outliers?
(b) Describe the pattern in the plot. What equation, if any, would summarize the variation?
(c) Transform both variables by taking the natural log of each, and then graph the loge CO2 versus the loge GDP. What pattern is apparent in the scatterplot?
(d) Fit an equation that summarizes the variation in the log-log scatterplot, using residuals to verify that the fit is appropriate.
(e) What is the implication of the fitted equation for the relationship between economic activity and CO2 production?
(f) Does your answer to the previous question change if you replace natural logs by base 10 logs?