A sampling method which involves a random start and then proceeds with the selection of every K element from then onwards is called (Where k = population size/sample size)?

1. A

   Snowball sampling

2. B

   Systematic sampling

3. C

   Stratified random sampling

4. D

   Simple random sampling

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

• Systematic sampling is a probability sampling method.
• It involves selecting samples based on a fixed, periodic interval, known as the sampling interval (k).
• The process begins by choosing a random starting point from the population list.
• After the random start, every k-th element is selected for the sample, where k is calculated by dividing the total population size (N) by the desired sample size (n).
• This method matches the description in the question perfectly.

Why Other Options Were Wrong

• Option A: Snowball sampling is a non-probability technique where participants are recruited through referrals from other participants. It does not use a fixed interval (k) or a random start from a complete list.
• Option C: Stratified random sampling involves dividing the population into distinct subgroups (strata) based on shared characteristics (e.g., age, gender) and then performing random sampling within each subgroup. It does not involve selecting every k-th element from the entire population.
• Option D: Simple random sampling gives every member of the population an equal chance of being selected, typically through a lottery system or random number generator. It does not follow a systematic pattern of selecting every k-th element.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Sampling Methods in Research as background academic context rather than a clinical decision trigger.
• Nurse researchers use systematic sampling for its simplicity and efficiency in large-scale studies, such as hospital-wide patient satisfaction surveys or quality audits.
• For example, a nurse manager could use systematic sampling to select every 10th patient chart for a documentation audit, ensuring an unbiased and representative review of practices.
• A key consideration is to ensure the list (sampling frame) does not have a hidden periodic pattern that aligns with the sampling interval, as this could lead to a biased sample.

How to Approach the Question

• First, carefully read the question to identify the key characteristics of the sampling method described. The keywords here are 'random start' and 'selection of every K element'.
• Next, recall the definitions of the different sampling methods provided in the options.
• Compare the description in the question stem with the definition of each option.
• Option A, Snowball sampling, relies on referrals, which is not mentioned.
• Option C, Stratified sampling, involves dividing the population into groups, which is not mentioned.
• Option D, Simple random sampling, gives everyone an equal chance but doesn't use a fixed interval 'k'.

Concept Tested & Keywords

• Concept Tested: Sampling Methods in Research
• Stem keywords: sampling method, random start, every K element, population size, sample size
• Lead-in keywords: is called

Question ID

Q0wDyMhwFnV2ObtH0jzR4G

Copy ID

Reference Book

E6 NursingResearch Suresh Sharma 5e Part 1 p. 239-241

E6 NursingResearch Sukhpal Kaur pp. 254-256, 253-255