Experimental Units: These are the individuals or objects on which measurements are taken in an experiment. For example, if you're conducting a study on the effects of a new drug, experimental units could be patients who receive different dosages.
Treatment Groups: In an experiment, treatment groups are created by assigning experimental units to receive specific treatments or conditions. For instance, if you're testing a new fertilizer on plants, you might have one group receiving the new fertilizer and another group receiving no fertilizer as a control.
Control Group: This refers to a specific treatment group in an experiment where no treatment is applied. It serves as a baseline for comparison against other treatment groups. In our plant fertilizer example, it would be the group that receives no fertilizer at all.