An experiment usually has three kinds of variables: independent, dependent, and controlled.

Essentially, a control variable is what is kept the same throughout the experiment, and it is not of primary concern in the experimental outcome. Any change in a control variable in an experiment would invalidate the correlation of dependent variables (DV) to the independent variable (IV), thus skewing the results.

Dependent variables are the variables that the scientist would be watching for any changes. It is necessary to keep all variables constant except the one you are investigating because changing something for one subject and not for the other would give false and inaccurate results, making the experiment null and void.

A part of the experiment that is not being tested and is used for comparison of the experimental results. A control group should be used when conducting an experiment. This group receives the same attention as the test groups, however, it will not be influenced by the variable the other groups are testing.

Variables are given a special name that only applies to experimental investigations. One is called the dependent variable and the other the independent variable. The independent variable is the variable the experimenter manipulates or changes, and is assumed to have a direct effect on the dependent variable.

The Six Steps

• Purpose/Question. Ask a question.
• Research. Conduct background research.
• Hypothesis. Propose a hypothesis.
• Experiment. Design and perform an experiment to test your hypothesis.
• Data/Analysis. Record observations and analyze the meaning of the data.
• Conclusion.

The basic steps of the scientific method are: 1) make an observation that describes a problem, 2) create a hypothesis, 3) test the hypothesis, and 4) draw conclusions and refine the hypothesis.

There are six common variable types:

• DEPENDENT VARIABLES.
• INDEPENDENT VARIABLES.
• INTERVENING VARIABLES.
• MODERATOR VARIABLES.
• CONTROL VARIABLES.
• EXTRANEOUS VARIABLES.

A variable in research simply refers to a person, place, thing, or phenomenon that you are trying to measure in some way. The best way to understand the difference between a dependent and independent variable is that the meaning of each is implied by what the words tell us about the variable you are using.

Every experiment has at least two variables—an independent variable and a dependent variable. The independent variable is what you are testing, and the dependent variable is the result. Any other variables in your experiment build on or affect the independent or dependent variables.

Such variables in statistics are broadly divided into four categories such as independent variables, dependent variables, categorical and continuous variables. Apart from these, quantitative and qualitative variables hold data as nominal, ordinal, interval and ratio. Each type of data has unique attributes.

Variables represents the measurable traits that can change over the course of a scientific experiment. In all there are six basic variable types: dependent, independent, intervening, moderator, controlled and extraneous variables.

A symbol for a value we don’t know yet. It is usually a letter like x or y. Example: in x + 2 = 6, x is the variable. But in something like y = x + 2 (a linear equation) x can have many values. In general it is much easier to always call it a variable even though in some cases it is a single value.

A variable is a quantity that may change within the context of a mathematical problem or experiment. Typically, we use a single letter to represent a variable. The letters x, y, and z are common generic symbols used for variables.

To pursue the goals, you need variables that make the process of goal setting possible to identify which results in the achievement of the goals. Therefore, research means the measurement of the variables and the importance of the variable is hidden in this concept.