Everyday we check the news and there is always something involving oil. Today it is considered common understanding how oil can have an effect on everything. Marginal analysis started a long time ago by forerunners such as Leon Walras, Carl Menger, and William Jevons. This evolved into neoclassical thinking by pioneers such as Alfred Marshall. Much of the principles of economics that we study today come from these schools of thought.
Walras is credited with furthering marginal analysis through general equilibrium. Through this he was able to demonstrate the effects of changes in supply and demand in all markets and not just a single one, for instance oil.
Partial equilibrium analysis held that everything remained unchanged, except for the variable being studied. General equilibrium analysis shows the how other factors can change. In the case of oil, a reduced quantity of oil will drive prices up. But this will also affect the demand for substitute goods such as coal. It also affects the price of gasoline and even things sucn as a the demand for automobiles and car washes.
All of this pertains exactly to managerial economics as we study regression analysis and use econometrics to find the demand for a firms product and the demand for inputs.