Introduction to Econometrics 3rd Edition by James Stock, Mark Watson

Exercise 17

A researcher studying the effects of a new fertilizer on crop yields plans to carry out an experiment in which different amounts of the fertilizer are applied to 100 different 1-acre parcels of land. There will be four treatment levels. Treatment level one is no fertilizer, treatment level two is 50% of the manufacturer's recommended amount of fertilizer, treatment level three is 100%, and treatment level four is 150%. The researcher plans to apply treatment level one to the first 25 parcels of land, treatment level two to the second 25 parcels, and so forth. Can you suggest a better way to assign treatment levels Why is your proposal better than the researcher's method