The variable that is changed in a scientific study to test the effect is called:

IGNOU PB Bsc Entrance-2022

Nursing Research & Statistic

Easy

Appeared in: IGNOU PB Bsc Entrance-2022

Explanation

The independent variable is the factor that a researcher intentionally manipulates, changes, or controls to observe its effect on an outcome.
In an experimental setup, it is considered the 'cause' in a cause-and-effect relationship.
It is also known as the 'manipulated variable' or 'treatment variable' in experimental studies (SRC_6287).
For example, in a study on the effect of a new teaching method on test scores, the teaching method is the independent variable.

Option B: The dependent variable is what is measured or observed as the outcome; it is the 'effect', not the factor that is changed by the researcher.
Option C: A confounding variable is an uncontrolled factor that can interfere with the results and provide an alternative explanation for the findings, not the variable intentionally changed by the researcher.
Option D: An extraneous variable is any variable, other than the one being manipulated, that could influence the outcome. Researchers try to control these, not change them as part of the test.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Types of Variables in Research Methodology as background academic context rather than a clinical decision trigger.
Understanding research variables is fundamental for nurses to critically appraise evidence-based practice literature and determine the validity of study findings.
In clinical practice, nurses often participate in or lead quality improvement projects, which require identifying an intervention (independent variable) and measuring its impact on a patient outcome (dependent variable).
What if? - If a study fails to control for confounding variables (e.g., patient comorbidities), a nurse reading the study should question the conclusion that the new treatment (independent variable) alone caused the improved patient outcome (dependent variable).

How to Approach the Question

First, analyze the question's core concept: it asks to identify a specific type of variable in a scientific study.
Focus on the keywords 'changed' and 'to test the effect'. This implies a variable that is actively manipulated by the researcher.
Recall the definitions of different research variables. The 'independent' variable is the one the researcher changes. The 'dependent' variable is the one that is measured (it 'depends' on the independent variable).
Evaluate the options based on these definitions. The 'independent variable' is the only one that fits the description of being intentionally changed to observe an effect.
Eliminate the other options: the dependent variable is measured, while confounding and extraneous variables are factors to be controlled, not manipulated as the primary test.

Concept Tested & Keywords

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E6 NursingResearch Suresh Sharma 5e Part 1 p. 87-89

E6 NursingResearch Sukhpal Kaur p. 97-99