Energy use. 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) in 1990 and 2004 for a sample of 96 countries

(unstats.un.org/unsd/mi/mi_goals.asp; accessed May 2008).

a) Find a regression model showing the relationship between 2004 Energy Use (reponse variable) and 1990 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 2004 Energy Use is explained by 1990 Energy Use?