Variables and Their Types
Variable is a concept which can take on different quantitative values. For example; height, weight, income, age etc. The main focus of the scientific study is to analyse the functional relationship of the variables. A variable is a quantity which can vary from one individual to another. The quantity which can vary from person to person.
“Variable is a property that taken on different value”,
Kerlinger
It is any feature or aspect of an event, function or process that, by its presence and nature, affects some other event or process, which is being studied.
(i) Continuous Variable:
It is that which can assume any numerical value within a specific range.
(ii) Discrete Variable:
A variable for which the individual values fall on the scale only with distinct gaps is called a discrete variable.
(iii) Dependent Variable or Criterion variable:
If one variable depends or is a consequence of other, it is termed as dependent variable. Criterion variable is the basis on which the effectiveness of the experimental variable is studied.
(iv) Independent Variable or Experimental Variable:
The variable that is antecedent to the dependent variable is termed as an independent variable. The variable whose effect is going to be known is known as experimental variable.
(v) Controlled Variable:
The effectiveness of an experimental variable is examined by comparing with other variable, known as controlled variable.
(vi) Confounding Variable:
Those aspects of study or sample, that might influence the dependent variable (outcome measures) ,and whose effect may be confused with the effects of the independent variable. They are of two types; Intervening and extraneous variable.
(vii) Intervening Variable:
There are a number of abstract variables in educational/social experiments, which intervene the effect of experimental or criterion variable. For controlling intervening variable appropriate research design should be used. Intervening variables are hard if not impossible, to observe because they usually have to do with an individual’s feelings like boredom, stress, fatigue, excitement etc. Extraneous variable on the other hand, are more readily observed or measured and thus are more easily controlled.
(viii) Extraneous Variable:
Independent variables that are not related to the purpose of the study, but may affect the dependent variable are termed as extraneous variables. Suppose the researcher wants to test the hypothesis that there is a relationship between children’s gain in social studies achievement and their self-concept. Here self-concept is independent variable and achievement in social study is dependent variable. Intelligence may as well affect the social studies achievement; but since it is not related to the purpose of the study undertaken by the researcher, it will be termed as extraneous variable. Whatever effect is noticed on dependent variable as a result of extraneous variable(s) is technically described as an ‘experimental error.’
A study must always be so designed that the effect upon the dependent variable is attributed entirely to the independent variables and not to some extraneous variable(s).When the dependent variable is not free from the influence of extraneous variable(s), the relationship between the dependent and independent variable is said to be confounded by an extraneous variable(s).
Extraneous variable can be controlled by removing the variable causing distraction. It may be eliminated by selecting cases with uniform characteristics and through randomization.
(ix) Organismic Variable:
There are some variables which cannot be manipulated. They are accepted by the researcher as they are. They are levels of intelligence, sex, class levels, and the like. The researcher can classify the subjects by sex but he cannot modify to suit his research condition. If a researcher attempts to compare boys and girls on some learning task, any differences might be attributed to sex differences but not necessarily so. The differences between boys and girls could be due to differences in intelligence, training, motivation or a myriad of other conditions present in all human beings and not necessarily to biological differences between sex. Those variables which cannot be manipulated and cannot themselves point out causal relations are called organismic variables.
