A sample design is the framework or plan for selecting a subset (sample) from a larger population. A good sample design ensures that the selected sample is representative, unbiased, and efficient, allowing the researcher to draw meaningful conclusions about the entire population.
Below are the key characteristics that define a good sample design:
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? 1. Representativeness
A good sample must accurately reflect the characteristics of the entire population. This means the sample should include all relevant subgroups and proportions similar to the population to avoid bias and ensure generalizability.
> Example: If 60% of a city’s population is female, then a representative sample should have around 60% females.
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? 2. Adequate Sample Size
The sample must be large enough to provide reliable and valid results. A small sample may lead to inaccurate conclusions, while an unnecessarily large sample increases time and cost without added benefit. The size should be determined based on the nature of the study, population variability, and margin of error.
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? 3. Precision and Accuracy
A good sample design should ensure that the estimates made from the sample are close to the true population values. This minimizes sampling errors and increases confidence in the research findings.
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? 4. Economy (Cost-effectiveness)
While maintaining accuracy, the sample design should also be economical. The method chosen should balance cost and resources with the desired level of accuracy.
> Note: Stratified sampling may cost more than simple random sampling, but it improves accuracy for diverse populations.
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? 5. Operational Simplicity
A good sample design must be simple to understand and implement. Complex procedures can lead to errors in execution and misinterpretation of results. The design should be practically applicable in the field.
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? 6. Flexibility
It should allow for adjustments or modifications in case of unexpected issues during data collection. Flexibility ensures that the sampling process can be continued even under constraints.
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? 7. Low Bias
The method should minimize selection bias and ensure randomization where possible. Bias can distort results and reduce the credibility of research findings.
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? 8. Time Efficiency
A good sample design saves time in data collection and analysis without compromising the reliability of results. It enables researchers to conduct the study within the given time frame.
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✅ Conclusion
A good sample design is the foundation of high-quality research. It must be representative, accurate, economical, unbiased, and practical. When these characteristics are met, researchers can confidently generalize their findings to the entire population, ensuring the study’s relevance and credibility.
