Questions: In an experiment to determine if a new type of fertilizer is better than the current "standard" fertilizer for growing corn, 20 plots of land were randomly assigned one of the two types. At the end of the growing season, the corn yields for each plot were measured. It was found that plots located closer to the highway had smaller yields than other plots. In this experiment, distance from the highway is:

In this experiment, distance from the highway is a confounding variable.

Explanation:

• A confounding variable is an external factor that can affect the results of an experiment, potentially leading to incorrect conclusions about the relationship between the variables being studied. In this case, the distance from the highway is affecting the corn yields, which could interfere with the assessment of the effectiveness of the new fertilizer compared to the standard one.
• The experiment aims to compare the effectiveness of two types of fertilizers on corn yield. However, the proximity to the highway is influencing the yield, which means it could confound the results by introducing an additional variable that was not controlled for in the experiment design.
• To accurately determine the effect of the fertilizers, the experiment should control for the distance from the highway, or at least account for its impact in the analysis, to ensure that any differences in yield are due to the fertilizer type and not the location of the plots.