The random sample survey is a commonly used method in market research and such surveys generally are considered to provide more robust results than purposive or convenience (such as quota) samples.

Consider a population in which the variable of interest tends to be at or near zero for many of the population units but a subgroup exhibits values distinctly different from zero. Such a population ...

K-means is comparatively simple and works well with large datasets, but it assumes clusters are circular/spherical in shape, so it can only find simple cluster geometries. Data clustering is the ...

Discover how simple random sampling ensures accurate and unbiased population research, offering efficiency and fairness over ...

Cluster randomized trials in health care may involve three instead of two levels, for instance, in trials where different interventions to improve quality of care are compared. In such trials, the ...