A researcher conducts a randomized experimental study where she randomizes participants to receive a high dosage weight loss pill a low dosage weight loss pill or a placebo pill. She assesses the number of pounds lost from baseline to post treatment for three groups. Her research question is. "Is there a difference between the three groups in the average weight lost? What is the dependent variable? What is the independent variable? What is the null hypothesis? What is appropriate statistical test to use?