I want to find out if rowing 1000 meters a day can decrease the amount of time you can run 1 mile. I randomly assign 500 college students to either rowing 1000 meters a day or not. Students who report to already be rowing 1000 meters a day are excluded from the study. I find that the average mile time for the rowing group was 9:15/mile and 10:05/mile for the non rowing group. I conclude that rowing can improve one's max mile time. What is the IV? What is the DV? What is the experimental group? What is the control group? Is my conclusion valid