Introduction
Sampling is an essential part of research that involves selecting a group of individuals or items from a larger population. Two commonly used sampling methods in educational research, especially in distance education, are random sampling and purposive sampling. These methods differ in how participants are selected and in the purpose they serve.
What is Random Sampling?
Random sampling is a probability sampling method where every individual in the population has an equal chance of being selected. This method ensures that the sample is unbiased and representative of the population.
Key Features of Random Sampling:
- Equal chance for every participant
- Minimizes selection bias
- Best for large and diverse populations
Example:
Suppose a distance education researcher wants to study satisfaction levels among students of IGNOU across India. They could randomly select 500 students from the university’s full enrollment list using a computer-based random number generator.
What is Purposive Sampling?
Purposive sampling is a non-probability method where the researcher intentionally selects individuals who have specific characteristics or knowledge relevant to the research topic. It is often used in qualitative research.
Key Features of Purposive Sampling:
- Participants are selected based on purpose or criteria
- Used when specific information is required
- Not statistically representative of the population
Example:
A researcher wants to study the challenges faced by visually impaired learners in distance education. They purposively select a group of 20 visually impaired students from different study centres who can share their experiences.
Differences Between Random and Purposive Sampling
| Aspect | Random Sampling | Purposive Sampling |
|---|---|---|
| Selection Method | Based on chance | Based on purpose or criteria |
| Bias | Minimizes bias | May include researcher bias |
| Use | Quantitative research | Qualitative or case study research |
| Representativeness | Statistically representative | Not statistically representative |
Conclusion
Both random and purposive sampling have their own uses in research. Random sampling is ideal for generalizing findings to a larger population, while purposive sampling is helpful when the researcher needs specific information from a particular group. The choice between the two depends on the goals, design, and scope of the research in distance education.