Populations, samples and bias
Pages
Populations and samples
The population as everyone of interest and the sample as the part surveyed.
Census or sample
When a census is worth it, and when cost or destructive testing forces a sample.
Random sampling
Giving every member an equal chance, and why haphazard is not random.
Non-random sampling
Systematic and opportunity sampling, and the groups each one quietly misses.
Bias in sampling
How time, place and selection method favour one group, and whom a survey misses.
Sample size
Why larger samples give steadier estimates, yet badly chosen ones stay biased.
Estimating population figures from a sample
Scaling a sample proportion up to the population, and the assumption behind it.
Practice
Populations and samples
The population as everyone of interest and the sample as the part surveyed.
PracticeCensus or sample
When a census is worth it, and when cost or destructive testing forces a sample.
PracticeRandom sampling
Giving every member an equal chance, and why haphazard is not random.
PracticeNon-random sampling
Systematic and opportunity sampling, and the groups each one quietly misses.
PracticeBias in sampling
How time, place and selection method favour one group, and whom a survey misses.
PracticeSample size
Why larger samples give steadier estimates, yet badly chosen ones stay biased.
PracticeSampling review
Populations, samples, bias and population estimates.