I have a cross sectional time series dataset that looks like this:
Country Year X1
France 2008 1
France 2009 2
France 2010 3
France 2011 4
France 2012 5
Germany 2008 1
Germany 2009 2
Germany 2010 3
Germany 2011 4
Germany 2012 5
Is there a simple approach to determining with a hypothesis test whether a linear or nonlinear regression is most appropriate for modeling X1's relationship with time? Solution within R is preferred. Thank you.
