Experimental Design

Experimental design is a research method in which researcher tries to examine causal effects by manipulating independent variable under controlled settings and measures whether it produces any change to the dependent variable. In an experiment experimenter deliberately imposes a treatment on a group of objects or subjects in the interest of observing the response. This differs from an observational study, which involves collecting and analyzing data without changing existing conditions. In an experimental design scientists try to find an experimental hypothesis. To support their hypothesis scientists measures to find significant difference between experimental group and control group when measuring a dependent variable which can be influenced by independent variable.
Independent variable: In an experiment independent variable is a factor or a treatment or something else that researcher manipulates to determine the cause-and-effect relations. An independent variable is a variable that researchers have control over, which they can choose and change as requires. Though in some cases values of independent variables can not be manipulated as they are fixed values and taken simply as given. For example, in experiment on the impact of alcohol and expectations on sexual arousal, the experimenters used two independent variables. The first variable was weather participants received the alcoholic drink or non-alcoholic drink. The second variable manipulated participants’ expectations. They were told either they that their drink contained alcohol or that it did not. In these cases independent variable is the alcohol.
Dependent variable: As the name suggests dependent variable is a variable which is dependent on another variable, the independent variable. In an experiment the factor that is measured by the researcher and apparently changes or gets affected by the influence of independent variable. In an experiment it is simply impossible to have a dependent variable