Revisiting your examples of Oligopoly and Monopolistic Competition

You know by now the different measures that are used to gauge the level of competition in a market. Information on concentration ratios and Herfindahl index are provided by the U.S Census Bureau, at http://www.census.gov/econ/concentration.html. This week, you will use these measures - plus your better understanding of market structures to revisit your examples of Oligopoly and Monopolistic Competition.

• First, find the NAICS (North American Industry Classification System) code for your industries at http://www.census.gov/eos/www/naics/. You can enter keywords in the search box (eg. If you type cereal, you will be told the NAICS code is 311230). You can, of course, simply use Google if you wish.
• Once you know the NAICS codes of your chosen industries, go back to http://www.census.gov/econ/concentration.html. Locate the appropriate industry by its 2-digit classification code. Then click on Link to Factfinder and click on the table that shows up. Scroll down till you find your 5-digit classification code, ie. your industry.
• What is the four-firm concentration ratio for your "example" industry?
• What is the value of the Herfindahl index?
• Combined, what do these measures tell you about the level of concentration / competition in this industry? Do they support your pick for an oligopoly?
• Repeat the above steps for your example of monopolistic competition. Assess the "goodness" of your example.