Controlled VariablesType of Rice Crop - The same type of rice should be grown throughout the experiment.Amount of Water - The irrigation should be consistent across the farm.Soil Quality - The soil should be similar in nutrient content and pH level.Independent VariablesUse of Bait (20g phosphorus material) - This is one method he uses to control mice.Presence of Scarecrow - This is another method aimed at deterring pests.Planting Peppermint - This is a third method used to repel mice.Dependent VariableRice Crop Yield - The amount of rice harvested, which is affected by the presence of mice and the methods used to control them.