Private closed economy
Aggregate expenditures are linked to real GDP in the aggregate appropriations model. The convergence of the collective expenditure curve with the 45-degree line in the model represents equilibrium, which occurs when aggregate expenditures approximate real GDP.
c. wright mills's sociological imagination suggest investigating to explain this increase?
a factory opens that mass-produces light bulbs.
not sure if that's an answer to your questions but this is an example! : )