Independent variable is:

Appeared in: HP CHO -9 October 2022

Explanation

The independent variable is defined as the presumed cause in a cause-and-effect relationship within a research study.
It is the variable that the researcher either manipulates (in experimental studies) or observes to determine its influence on another variable.
For example, in a study on the effect of a new drug on blood pressure, the drug (or its dosage) is the independent variable.

Option A: This is incorrect because the independent variable is the very factor that is manipulated or changed by the researcher in an experimental study to observe its effect.
Option C: This describes the dependent variable. The dependent variable is the outcome or effect that is measured to see if it changes in response to the independent variable.
Option D: 'Outcome variable' is a synonym for the dependent variable, especially in non-experimental studies. It represents the result or effect being studied.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Definition of Independent Variable in Research as background academic context rather than a clinical decision trigger.
Understanding the difference between independent and dependent variables is fundamental for nurses to critically appraise research studies and apply evidence-based practice.
When evaluating a study on a new wound care dressing (independent variable) and its effect on healing time (dependent variable), a nurse can assess if the study's conclusion is valid.
What if? If a study is observational (non-experimental), the independent variable (e.g., smoking) is not manipulated but is called a 'predictor variable,' and its relationship to the 'outcome variable' (e.g., lung cancer) is observed.

How to Approach the Question

First, identify the key term in the question stem, which is 'Independent variable'.
Recall the basic definition of variables in research methodology. Think of it as a cause-and-effect relationship.
Evaluate each option against this definition. The independent variable is the 'cause'.
Option A is incorrect because the IV is often manipulated.
Option B, 'Presumed cause', directly matches the definition.
Options C and D, 'Presumed effect' and 'outcome variable', are definitions for the dependent variable. Therefore, they are incorrect.

Concept Tested & Keywords

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

E6 NursingResearch Sukhpal Kaur p. 97-99

Practise the full HP CHO -9 October 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.