In a short essay, list and discuss the four probability sampling techniques used in marketing research

What will be an ideal response?

a. In simple random sampling, each element in the population has a known and equal probability of selection. Furthermore, each possible sample of a given size has a known and equal probability of being the sample actually selected. The implication in a random sampling procedure is that each element is selected independently of every other element.
b. In systematic sampling, the sample is chosen by selecting a random starting point and then picking every ith element in succession from the sampling frame. The frequency with which the elements are drawn, i, is called the sampling interval. It is determined by dividing the population size N by the sample size n and rounding to the nearest integer.
c. Stratified sampling involves a two-step sampling process, producing a probability rather than a convenience or judgment sample. First, the population is divided into subgroups called strata. Every population element should be assigned to one and only one stratum, and no population elements should be omitted. Second, elements of each stratum are then randomly selected. A major objective of stratified sampling is to increase precision without increasing cost.
d. In cluster sampling, the target population is first divided into mutually exclusive and collectively exhaustive subpopulations, or clusters. Then a random sample of clusters is selected, based on a probability sampling technique. For each selected cluster, either all the elements are included in the sample or a sample of elements is drawn probabilistically. If all the elements in each selected cluster are included in the sample, the procedure is called one-stage cluster sampling. If a sample of elements is drawn probabilistically from each selected cluster, the procedure is two-stage cluster sampling.