5. Go to the Marketplace section (section B) of The Wall Street Journal and find an article about a specific industry (automobiles, toothpaste, etc.) that includes information about the market shares held by the largest firms in the industry. Based on the data provided, calculate the concentration ratio (CR4) for the top four firms. Then figure the Herfindahl index based on the information provided. Remember that the Herfindahl index is not significantly increased by small market shares (e.g., 1 x 1 = 1; 2 x 2 = 4), so do not worry about the smaller market shares that may not be provided in the article.

Sometimes the market share data will be provided in a pie chart which accompanies the article. In other cases, the information will be contained in the article itself. The market share data may include a category labeled "other". Do not use this category in calculating the CR4 or the Herfindahl index.

In addition to figuring the CR4 and the Herfindahl index, write a short essay of about 100 words describing the market structure applicable to this industry. Give reasons to support your classification.

Please print out and submit all of your extra credit answers at the end of the course. One point will be added to your final exam score or WSJ project for each valid answer.

6. Review the characteristics of a monopolistically competitive market on pp. 640-641 in your text.