What is a Representative Sample Size for a Survey?
This common question mixes two concepts: representativeness and sample size. Representative samples mean asking the people in your population of interest. It is more important to ask a few of the right people what they think than a lot of the wrong people. Once you're talking to the right people you need to identify the highest margin of error you or the survey sponsor can tolerate then compute the sample size.
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Featured Product: Survey Sample Size Package
Have you ever been asked how large a sample size you need for a survey? I put together a 23 page step-by-step guide and Excel calculator
that will allow you to intelligently answer this common question. The guide and calculators:
See more about the Survey Sample Size Package
- Generate sample sizes for rating scale and binary response items
- Contain a five-step process for finding the right sample size
- Use industry defaults to estimate unknown standard deviations (a common problem for sample size estimates)
- Contain four detailed examples and five practice exercises to help you understand the formulas and process
- Show you how to find the right sample size for the popular Net Promoter Question and other Top-2 box questions
- Provide confidence intervals around responses
If you've purchased the premium report "How to Conduct a Quantitative Usability Test" or the Quantitative Starter package get 15% off the Survey Sample Size Package until July 31st. Just login to your account
to receive the discount.
I will be teaching a statistics tutorial
this weekend with Jim Lewis at the Applied Human Factors and Ergonomics
(AHFE) International Conference. If you're in Miami or at the conference be sure to send us a note.
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