Question

Use the following study to answer the following question. A researcher applies varying amounts of fertilizer (0, 2, 4, 8, 10 units) to 50 potted tomato plants. All other variables that may affect the outcome (watering, temperature, sunlight, plant size, etc) are kept from pot to pot. At the end of the growing season, the tomatoes grown on each plant are weighed to determine which fertilizer level produces the largest tomato yield. Is the study presented above a controlled experiment?

Answer 1

Yes this would be a controlled experiment because all the variables would be kept the same for all the tomato plants except for the fertilizer amounts so any changes in the tomatoes can be attributed to the fertilizer amounts and thus an accurate idea of the affect of the particular fertilizer can be determined.