Question

Why is it important for the researcher to control extraneous environmental and social variables in an experiment? How does a researcher do this?

what is the minimum number of IV conditions in an experiment?

What are experimental and control groups? Do all experiments have to have a control groups?

What are experimental and control groups? Do all experiments have to have a control group.

How can you tell if a variable can serve as an IV?

Answer 1

1. Extraneous variables are those variables that moderate the relationship between the independent variable and the dependent variable but the researcher does not want this interference of the extraneous variable. It is important for the researcher to control the extraneous variable are those that operate in the experimental situation in addition to the independent variables and affect the dependent variable. Techniques of controlling extraneous variables-

• The technique of elimination- It is the simplest way to control the extraneous variable is to eliminate it completely from the experimental situation. For example, if noise is the extraneous variable make a soundproof room.
• The constancy of conditions- Extraneous variables controlled by holding their values constant for all participants in all conditions.
• Balancing- Experimenters give equal treatment to all subjects but the experimental group is treated in a different ways from the control group.
• Counterbalancing- It uses to control the extraneous variable of the amount of practice and fatigue. It is based on the principle that each condition must occur an equal number of times at each stage of practice.
• Randomization- It is a technique in which each member of the population has an equal and independent chance of being selected. So it randomly distributes the extraneous effect over the experimental and control group.

2. The minimum number of IV conditions in an experiment should be two so that results can be interpreted on the basis of comparison.

3.

Experimental group- It is also known as the treatment group. This is a group that receives treatment in the research or a group of participants exposed to the independent variable.

Control group- It is the group that does not receive treatment or does not exposed to the independent variable.

It is important to have a control group in an experiment. It works as a baseline in the experiment so that results of the experimental groups can be compared with it see the impact of independent variable on dependent variable. It is not essential but it is desirable in an experiment.

4. We can say that this is a can serve as an IV if a variable can be manipulated, measured, and influence dependent variable.