Statistics · Ch 7 — Sampling Methods
Census Method and Sample Method
Census Method and Sample Method
Once a population is identified, an investigator has two broad ways to collect data about it: study every single unit (the census method) or study only a part of it (the sample method).
Census Method (Complete Enumeration): Every unit of the population is individually observed, measured, or surveyed; no unit is left out. The Population Census of India, conducted every ten years, is the best-known example — every household in the country is counted.
Sample Method: Only a carefully selected subset of the population is studied, and the findings are generalised to the whole population using statistical inference. Most business surveys, opinion polls, and quality-control checks use the sample method because studying every unit is neither necessary nor practical.
| Basis | Census Method | Sample Method |
|---|---|---|
| Coverage | Every unit of the population | Only a part (sample) of the population |
| Cost | Very high | Comparatively low |
| Time required | Very long | Comparatively short |
| Feasibility for destructive testing | Not possible (testing every bulb produced would destroy the whole stock) | Possible — only a few units are tested |
| Accuracy | No sampling error, but more prone to non-sampling error due to sheer scale | Sampling error exists, but careful, well-supervised work often keeps non-sampling error low |
| Suitability | Small, easily accessible populations; official counts required by law | Large or very large populations; when quick, low-cost results are acceptable |
A GSEB Std 11 Business Mathematics and Statistics learner should be able to justify, for any given situation, whether a census or a sample method is the more suitable choice. …
Every unit of the population is individually studied; also called complet …
Only a selected part of the population is studied, and results are generalised to the w …