Question

You are conducting an experiment to determine whether herbicides that are being used to control invasive weeds have negative side effects on native beetles. For your experiment, you divide a field filled with invasive weeds into two halves and apply herbicide to one of the halves. You then randomly place 10 4x4 m plots in each half of the field and sample each plot to determine beetle density. You determine that there are significantly fewer beetles in the half of the field that received the herbicide treatment and concludide that the herbicide has negative side effects on the native beetles. Is this a valid conclusion? Why or why not?

Answer 1

Yes, it is a valid conclusion, this being a very well defined experiment with both control and treatment group which have been randomly determined. These plots are further subdivided into smaller plots while being sampled for the beetle density. The conclusions from the test based on our analysis of the beetle density in the individual randomly placed 10 4x4 m plots in each half of the field, which further helps account for variability, reducing the margin of error, and making our results even more reliable. Thus the conclusions drawn are good and valid.