Compare the advantages and disadvantages of the two types of collecting a sample.

Question

What will be an ideal response?

Answer 1

There are two basic types of sampling: probability sampling and nonprobability sampling. With probability sampling, every element in the population being studied has a known chance of being selected for study. Random sampling is a form of probability sampling. When marketers employ random sampling, all the units in a population have an equal chance of appearing in the sample. Another type of probability sampling is stratified sampling, in which the population of interest is divided into groups according to a common attribute, and a random sample is then chosen within each subgroup. A stratified sample may reduce some of the error that is a risk of a completely random sample, ensuring that a group is not accidentally overrepresented. By segmenting a population into groups, the researcher makes sure that each segment receives its proportionate share of sample units and helps investigators avoid including too many or too few sample units from each subgroup. Samples are usually stratified when researchers believe there may be variations among different types of respondents.The second type of sampling, nonprobability sampling, is more subjective than probability sampling because there is no way to calculate the probability that a specific element of the population being studied will be chosen. Quota sampling, for example, is highly judgmental because the final choice of participants is left to the researchers. In quota sampling, researchers divide the population into groups and then arbitrarily choose participants from each segment. In quota sampling, researchers impose some controls-usually limited to two or three variables, such as age, gender, or race-over the selection of participants to ensure that representative categories of respondents are included.