A well-designed experiment needs to have an independent variable and a dependent variable. The independent variable is what the scientist manipulates in the experiment. Therefore, the dependent variable provides the data for the experiment. Experiments must contain the following steps to be considered “good science.”

Disadvantages. The main disadvantage with between-group designs is that they can be complex and often require a large number of participants to generate any useful and reliable data.

Between-Subject Experimental Designs

1. An independent variable is manipulated to create at least two treatment conditions.
2. A dependent variable is measured within each treatment condition.
3. The scores measured in each condition are compared.
4. All other (extraneous) variables are controlled.

Experimental design means creating a set of procedures to test a hypothesis….

1. Step 1: Define your research question and variables. You should begin with a specific research question in mind.
2. Step 2: Write your hypothesis.
3. Step 3: Design your experimental treatments.
4. Step 4: Assign your subjects to treatment groups.

An experiment may include multiple experimental groups at one time. A control group is a group separated from the rest of the experiment such that the independent variable being tested cannot influence the results. While all experiments have an experimental group, not all experiments require a control group.

An experimental group (sometimes called a treatment group) is a group that receives a treatment in an experiment. For example, a human experimental group could receive a new medication, a different form of counseling, or some vitamin supplements.