Does A Large Sample Size Guarantee A Representative Sample?
Posted on May 13, 2010 I often get asked “What sample size do I need to get a representative sample?” The problem is that this question is not formulated correctly. Sample size and representativeness are two related, but different issues. The sheer size of a sample is not a guarantee of its ability to accurately represent a target population. Large unrepresentative samples can perform as badly as small unrepresentative samples. A survey sample’s ability to represent a population has to do with the sampling frame; that is the list from which the sample is selected. When some parts of the target population are not included in the sampled population, we are faced with selection bias, which prevent us from claiming that the sample is representative of the target population. Selection bias can occur in different ways: • Convenience sample: This includes respondents who are easier to select or who are most likely to respond. This sample will not be representative of harder-to-select individu
Related Questions
- How can a sample of 1,000 be representative of a nation with 50 million people? Don you need more for a large country than a small country?
- Which of the following is true regarding the sampling distribution of the mean for a large sample size?
- Is the sample size large enough to yield reliable estimates?
