Energy use and recession. The Great Recession of 2008 changed spending and energy use habits worldwide.

Based on data collected from the United Nations Millennium Indicators Database related to measuring the goal of ensuring environmental sustainability, investigate the association between energy use (kg oil equivalent per $1000 GDP) before (2006) and after (2010) the crisis, for a sample of 33 countries (unstats.un.org/unsd/mi/mi_goals.asp;

accessed June 2013).

a) Find a regression model showing the relationship between 2010 Energy Use (response variable) and 2006 Energy Use (predictor variable).

b) Examine the residuals to determine if a linear regression is appropriate.

c) Test an appropriate hypothesis to determine if the association is significant.

d) What percentage of the variability in 2010 Energy Use is explained by 2006 Energy Use?