The variable an experiment measures is called the dependent variable. The variable is dependent on the independent variable which is being controlled by the researcher. Experiments try to identify the effects the independent variable causes on the dependent variable (Flannelly et al., 2014). On the other hand, extraneous variables refer to all variables in an experiment that could have effects on the experiment but are not independent variables. In an experiment, only the independent variable should have effects on the dependent variable. Therefore, researchers try to control the extraneous variables.
Two ways that researcher control extraneous variables are through random sampling and Experimental designs. In random sampling, they do not take away the variables but make sure they are equal in all groups. In experimental design, researchers reduce or completely remove the extraneous variables (Kaya, 2015).
Kaya, C. (2015, January 23). Internal validity: A must in research designs. https://doi.org/10.5897/ERR2014.1835
Flannelly, L., Flannelly, K. & Jankowski, K. (2014, September 25). Independent, dependent, and other variables in Healthcare and Chaplaincy Research. https://doi.org/10.1080/08854726.2014.959374
Variables in research are defined as an attribute of an object that is being studied. There are six types of variables in research which are dependent, independent, moderator, intervening, extraneous and controlled variables. The purpose of this paper is to explore independent, dependent, and extraneous variables and to explain how to control the extraneous variable.
Independent Variables are the variable that a researchercontrols or changes during a study. It has a direct effect on the dependent variable. An example of an independent variable is gender or level of education. On the other hand, the dependent variable is the variable that the researcher is measuring or testing during a study. The dependent variable depends on the independent variable. An example of a dependent variable is nutrition status, which depends on the independent variable level of education (Kaur, 2013). There is also the extraneousvariables, which are variables that the researcher is not intentionally studying in the experiment, but they negativelyinfluence the results of the study. There are various types of extraneous variables. The first type is participant variables, where the participants have prior knowledge or health status that could influence the study’s outcome. The second type is the situational variable, which includes lighting, temperature, or other environmental factors that may influence the study’s outcome. Thirdly is investigator effects, where the researcher unintentionally affects the study results by giving clues to the study participants on how they should act during the study.
Extraneous variables can be controlled by random sampling. Although random sampling does not eliminate extraneous variables, it ensures that they are equally distributed in both study groups. Secondly, situational variables, which areamong extraneous variables, become controlled by ensuring that the researcher controls the environment where the study takes place by keeping the noise and temperature levels and other environmental conditions constant.
Kaur, S. P. (2013). Variables in research. Indian Journal of Research and Reports in Medical Sciences, 3(4), 36-38.http://www.hu.usp.br/wpontent/uploads/sites/598/2019/09/complemento-aula-1.pdf