Independent Variable Manipulated Variable- What will you be changing in the experiment?

Since "manipulated" means changed by a person, then you must be changing the manipulated variable.

They are different terms for the same thing.

An independent variable is the potential stimulus or cause, usually directly manipulated by the experimenter, so it could also be called a manipulative variable.

A dependent variable is the response or measure of results.

Extraneous variables — other than the independent variable — potentially can affect the dependent variable, so they must be controlled. If possible, you try to keep them constant between the experimental and control group.

The experimental group receives the independent variable.

The control group is similar to experimental, except it does not receive the independent variable. Extraneous variables are balanced between experimental and control groups.

Types of experiments

1. Single blind gives the control group a placebo — a substance that is inert, it has no physical effect. Subjects don't know if they are in experimental or control group to reduce placebo effect, a change in behavior solely due to believing that you are getting the independent variable.

2. Double blind keeps both subjects and experimenter ignorant of group setup. Distribution of the independent variable and placebo are controlled by third party. This controls for experimenter bias and self-fulfilling prophecy, which means that experimenters with particular expectations are likely to consciously or unconsciously to bias the experiment and influence it to conform to their expectations.

As an example, suppose you want to find out if fluorides reduce dental cavities. You would find two groups, trying to control the extraneous variables. Extraneous variables are found by surveying previous research in the area. In this case, you would match the groups in terms of previous history of cavities, diet and dental hygiene habits including how and how often they brush their teeth.

The experimental group would get toothpaste with the independent variable, the fluoride, while the control group would not have the fluoride in their toothpaste. The toothpaste without the fluoride would be the placebo.

The dependent variable would be the number of cavities after participating in the experiment for a time. The dependent variable indicates the results, but it is not the results. At the end of the experiment, both groups could have no change in cavities or one of the groups could have a greater reduction in cavities. (Of course, if the fluoride increased cavities, you wouldn't want to use it.) All of these varied results would be indicated in terms of the dependent variable.

If only the subjects do not know who is getting the fluoride, it is a single blind experiment. If both the subjects and experimenter do not know, it is a double blind.

The manipulated variable, also known as the independent variable, is the factor that the researcher purposely changes or manipulates in an experiment. It is the variable that is believed to have an effect on the dependent variable, which is the variable that changes in response to the manipulated variable. In an experiment, the researcher might manipulate factors such as time, temperature, concentration, or a specific treatment in order to observe the effect on the dependent variable.

To identify the independent variable or manipulated variable in an experiment, you need to determine what factor or condition you, as the researcher, will deliberately change or manipulate. This variable is the one hypothesized to have an effect on the dependent variable, which is the outcome or result observed in the experiment.

To identify the independent variable, consider what factors you will purposely manipulate or alter between different experimental conditions. It should be something within your control. For example, in a study investigating the effect of sunlight on plant growth, the independent variable would be the amount of sunlight the plants receive.

To summarize, the independent variable is the condition or factor that is intentionally manipulated by the researcher in an experiment. It is the variable hypothesized to cause a change or effect on the dependent variable.