Which of the following is an example of probability sampling?

UPPSC-2021

Nursing Research & Statistics

Easy

Appeared in: UPPSC-2021

Explanation

Systematic sampling is a form of probability sampling where a random starting point is selected and then every 'kth' element in the population list is chosen.
The key feature that makes it a probability method is the random start, which gives every element a known chance of being selected.
This method is often more convenient than simple random sampling and can be more precise if there is a hidden order in the population list.

Option A: Purposive sampling is a non-probability method because participants are selected based on the researcher's judgment and knowledge of the population, not by a random process.
Option B: Quota sampling is a non-probability method. Although it ensures certain subgroups are represented in proportion to their presence in the population, the actual selection of individuals within those subgroups is done by convenience, not randomly.
Option D: Convenience sampling is a non-probability method where participants are selected based on their easy availability and accessibility to the researcher. It does not involve random selection.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Types of Sampling Methods in Research as background academic context rather than a clinical decision trigger.
For nurses, understanding sampling methods is essential for critically appraising research evidence. It helps determine if a study's findings are credible and can be generalized to their own patient populations.
A study on a new nursing intervention that uses a non-probability sample (e.g., convenience) may have limited applicability outside the specific context where it was conducted.
What if? If a researcher wanted to compare the job satisfaction of nurses across different hospital types (public, private, and trust-run), a stratified random sampling method would be superior to systematic sampling. Stratified sampling would ensure that an adequate number of nurses are randomly selected from each hospital type, allowing for meaningful comparisons between the groups.

How to Approach the Question

First, identify the core concept in the question, which is 'probability sampling'.
Recall the definition of probability sampling: a method where every member of the population has a known, non-zero chance of being selected. This allows for the generalization of findings.
Evaluate each option against this definition.
Analyze 'Purposive', 'Quota', and 'Convenient' sampling. Recognize that these methods rely on the researcher's judgment, convenience, or pre-set non-random quotas, so they are non-probability methods.
Analyze 'Systematic' sampling. Recall that it involves a random start and a fixed interval ('kth' element), which fulfills the criteria for a probability sampling method.

Concept Tested & Keywords

Qp_uyHuzEsKcV178Tkcs0w

E6 NursingResearch Polit 11e Part 1 p. 279-281

E6 NursingResearch Suresh Sharma 5e Part 1 p. 245-247

E6 NursingResearch Sukhpal Kaur p. 260-262