can someone better explain to me what the independent/manipulated variable is in an experiment. also, i am not clear on what the dependent/responding variable is.
please help
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.
This may be more than you wanted, but I hope it helps. Thanks for asking.
Sure! I'd be happy to explain!
In an experiment, the independent variable (also known as the manipulated variable) is the variable that the researcher intentionally changes or controls. It is the factor that is being studied to determine its effect on the dependent variable. The purpose of manipulating the independent variable is to see how it influences the outcome of the experiment.
On the other hand, the dependent variable (also known as the responding variable) is the variable that is being measured or observed during the experiment. It is the outcome or result that may be affected by the changes to the independent variable. The value of the dependent variable is expected to change in response to the manipulations made to the independent variable.
To better understand the independent and dependent variables, let's consider an example. Imagine you are conducting an experiment to investigate how different amounts of fertilizer affect the growth of plants. In this case:
- The independent variable/manipulated variable would be the amounts of fertilizer you provide to the plants. You would intentionally change the doses of fertilizer to see how they influence plant growth.
- The dependent variable/responding variable would be the growth of the plants. You would measure the height, number of leaves, or any other relevant factor to assess the effect of different fertilizer amounts on plant growth.
To summarize, the independent variable is the variable that is intentionally changed or manipulated in an experiment, while the dependent variable is the variable that is being observed or measured, and is expected to be influenced by the independent variable.