Solutions to Assignments
IBO-02 International Marketing Management
Solutions to Question No. 4
a) Probability and Non-probability Sampling Methods
Sampling means selecting a particular group or sample to represent the entire population. Sampling methods are majorly divided into two categories probability sampling and non-probability sampling. In the first case, each member has a fixed, known opportunity to belong to the sample, whereas in the second case, there is no specific probability of an individual to be a part of the sample.
For a layman, these two concepts are same, but in reality, they are different in the sense that in probability sampling every member of the population gets a fair chance of selection which is not in the case with non-probability sampling. Other important differences between probability and non-probability sampling are compiled in the article below.
The significant differences between probability and non-probability sampling
- The sampling technique, in which the subjects of the population get an equal opportunity to be selected as a representative sample, is known as probability sampling. A sampling method in which it is not known that which individual from the population will be chosen as a sample, is called non-probability sampling.
- The basis of probability sampling is randomization or chance, so it is also known as Random sampling. On the contrary, in non-probability sampling randomization technique is not applied for selecting a sample. Hence it is considered as Non-random sampling.
- In probability sampling, the sampler chooses the representative to be part of the sample randomly, whereas, in non-probability sampling, the subject is chosen arbitrarily, to belong to the sample by the researcher.
- The chances of selection in probability sampling, are fixed and known. As opposed to non-probability sampling, the selection probability is zero, i.e. it is neither specified not known.
- Probability sampling is used when the research is conclusive in nature. On the other hand, when the research is exploratory, non-probability sampling should be used.
- The results generated by probability sampling, are free from bias while the results of non-probability sampling are more or less biased.
- As the subjects are selected randomly by the researcher in probability sampling, so the extent to which it represents the whole population is higher as compared to the non-probability sampling. That is why extrapolation of results to the entire population is possible in the probability sampling but not in non-probability sampling.
- Probability sampling test hypothesis but non-probability sampling generates it.