What is Variable ?
Define: Variable is a concept which can take on different quantitative values.
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”,
For example; height, weight, income, age etc.
According to Kerlinger, ‘A variable is a property that takes on different values. Putting it
redundantly, a variable is something that varies … A variable is a symbol to which numerals or values
are attached’
Types Of Variables
1. Dependent Variable or Criterion variable: If one variable depends or is a consequence of other, it is termed as
dependent variable. Dependent variable is the basis on which the
effectiveness of the experimental variable is studied.
Dependent variables are influenced by one or
more independent variables.
2. Independent variable : the cause supposed to be responsible for bringing about change(s) in a
phenomenon or situation. The variable whose effect is going to be known.Independent variable can be changed by researcher and its results shown on dependent variable.
Ex - "Time Spent Studying" is the independent variable and "Marks obtained" is the dependent variable.
3. Intervening Variable: These are also
termed as mediator variables. They establish
link between IV and DV. These are variables
through which one variable affects another
variable. These are helpful to understand the
process.
For example, tissue damage or lung cancer due to smoking is an intervening variable. Here Smoking is independent variable and lung cancer or tissue damage are dependent variable and both are considred as a intervening variable.
4. Controlled Variable: The effectiveness of an experimental variable is examined by comparing
with other variable, known as controlled variable.
5. 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.
Extraneous variable can be controlled by removing the variable
causing distraction. It may be eliminated by selecting cases with uniform
characteristics and through randomization.
6.Discrete Variable: A variable for which the individual values fall on the scale only with
distinct gaps is called a discrete variable.
7. Organismic Variable: There are some variables which cannot be manipulated. They are
accepted by the researcher as they are. Those variables which cannot be manipulated and cannot
themselves point out causal relations are called organismic variables.
8. Constant variable: has only one category or value, for example taxi, tree and water;
Measuring Variables
Measurement of variables is central to research
studies. According to Stevens, measurement
scales can be of four types:
1. Nominal scale: It is also termed as classifi
catory scale. A variable being measured on
a nominal scale may have one, two, or more
subcategories depending upon the extent of
variation. For example, gender can be clas
sified into two subcategories—male and
female
2. Ordinal or ranking scale: It usually ranks
the subgroups in a certain sequence or
order.
For example, examination marks can
be measured either quantitatively, that is,
in absolute terms or in percentage terms or
qualitatively using subcategories like above
average, average, and below average.
3. Interval scale: An interval scale has all the
characteristics of an ordinal scale. In addi
tion, it uses a unit of measurement with an
arbitrary starting and terminating points.
For example, Celsius scale is from 0°C to
100°C.
4. Ratio scale: They are used to gather quanti
tative information. It combines the proper
ties of nominal, ordinal, and interval scales. In addition, it has its own property. It has a
fixed starting point. Ratio scale consists
of equidistant points and has a meaningful
zero point.