Types of Variables - Independent Dependent Extraneous Intervening Moderator Variables.

Types of Variables - Independent Dependent  Extraneous  Intervening Moderator

What is Variable ?


Variables is “a quantity that may have a number of different values.”
Which is Measurable, Changeable or Unstable
A variable is something that has at least two values
It is also important that the all values of the variable be observable.
Variable is a property that takes on different values (person to person, subject to subject)
It is also a logical grouping of attributes. Attributes are characteristics or qualities that describe an object.


Types of Variables

Independent Variable
Dependent Variable
Intervening/Mediating Variable
Extraneous Variable
Moderator variable

Independent Variable

Variable that is presumed to influence other variable
It is the presumed cause, whereas the dependent variable is the presumed effect.

Dependent Variable

Variable affected by the independent variable
It responds to the independent variable.

Example

“How stress affects mental state of human beings?”
Independent variable ----- Stress
Dependent variable ---- mental state of human
beings You can directly manipulate stress levels in your human subjects and measure how those stress levels change mental state.

Intervening/Mediating Variable

It is a variable whose existence is inferred but it cannot be measured.

Example

“Higher education typically leads to higher income”

Higher education----(independent variable)
Higher income----(dependent variable)
Better occupation---- intervening variable
It is causally affected by education and itself affects income.

Extraneous Variable

Extraneous variables are undesirable variables that influence the relationship between the variables an experimenter is examining.


Example
“An educational psychologist has developed a new learning strategy and is interested in examining the effectiveness of this strategy”

The experimenter randomly assigns students into two groups. All of the students study text materials on a biology topic for thirty minutes.

One group uses the new strategy and the other uses a strategy of their choice.

Then all students complete a test over the materials.
Extraneous variable ------ pre-knowledge of the biology topic

Moderator variable

It is a type of an independent variable that may not be the main focus of the study
It is a characteristics of individuals or of treatment variables that may result in an interaction between an independent variable and other variables
It may modify the relationship between the independent variable and the dependent variable

Example

when dealing with any research question, gender may affect them.