The power analysis is used to estimate

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2022

Nursing Research & Statistics

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2022

Explanation

Power analysis is a statistical method used to determine the appropriate sample size for a study.
Its primary purpose is to ensure a study has enough statistical power (typically 80%) to detect a real effect if one exists.
By calculating the minimum required sample size, researchers can avoid conducting underpowered studies, which risk producing false-negative results (Type II errors).
It balances the risk of errors with the practical constraints of time and resources.

Option A: The level of significance (alpha) is a predetermined threshold set by the researcher before the study. It is an input for the power analysis calculation, not the output.
Option B: Internal validity refers to the degree of confidence that the causal relationship being tested is trustworthy and not influenced by other factors or variables. It is related to study design and control of confounding variables, not statistical estimation of sample size.
Option C: Reliability refers to the consistency and repeatability of a measurement instrument or tool. It is a quality of the data collection method, not a quantity estimated by power analysis.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Purpose of Power Analysis in Research as background academic context rather than a clinical decision trigger.
In nursing research, conducting a power analysis is an ethical obligation. It prevents enrolling more participants than necessary and avoids wasting resources on studies too small to yield valid results.
An adequately powered study ensures that findings from nursing interventions are trustworthy, providing a solid evidence base for clinical practice changes.
What if? A researcher skips power analysis and uses a small 'convenience' sample. The study would likely be underpowered, increasing the risk of a Type II error. A beneficial nursing intervention (e.g., a new wound care technique) could be mistakenly deemed ineffective, preventing its adoption and hindering patient care improvement.

How to Approach the Question

First, identify the key term in the question stem, which is 'power analysis'.
This is a factual recall question from the subject of Research and Statistics. Recall the definition and primary purpose of this statistical procedure.
The main goal of a power analysis is to determine how large a sample needs to be for a study to have a reasonable chance of detecting a real effect.
Evaluate the options based on this definition. 'Sample Size' is the direct output of a power analysis.
Eliminate the other options by defining them: 'Level of Significance' is an input for the analysis, while 'Internal Validity' and 'Reliability' are distinct research concepts related to study design and measurement quality, respectively.

Concept Tested & Keywords

Qg7etrbD38ixP2ubUvzeiQ

E6 NursingResearch Suresh Sharma 5e Part 1 p. 250-252

E6 NursingResearch Polit 11e Part 1 p. 419-421