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 ...

1. Distinguish between probability and non-probability sampling and discuss the advantages and disadvantages of each. If you can not specify the probability that any given individual will be in the ...