Question

What is non probability sample? Discuss and give example

Answer 1

A sample is any number of individuals taken from the population for the purpose of research analysis. A sample is considered to be the true representation of a population. There are different methods of collecting a sample. The two methods are; Probability Sampling and Non-Probability Sampling.

Probability Sampling is when every individual has equal, probable chances of being selected in the sample. Non-Probability Sampling on the other hand, provides no accurate basis of including individuals in a sample and them being the true representation of the population. The whole idea behind sampling is to extract a smaller amount of individuals from a worldwide population while still representing the population.

Convenience Sample is a method of Non-Probability Sampling. It is also known as Accidental Sampling. It is one of the most common methods used since it is economical and convenient. In this kind of a sampling method, the investigator chooses his sample not based on how well the sample represents the population but chooses according to his convenience. For instance, the researcher wants to see the effect of different kinds of learning techniques on different treatment groups. For this experiment, the researcher needs a sample of students from different classes. The experimenter, chooses the sample of grade 10 students, as their class teacher is his best friend. He chose this sample for his convenience and not because it is a representation of the population.

Convenience Sampling has a massive advantage over other methods of sampling and thus, is the most common method used. It is very economical, the costs involved are minimal and the sample is readily available. No extra efforts are to be taken. However, it has some disadvantages. Firstly, it is not the true representation of the population which means that the results of the research may not be accurate. Also, since in accidental sampling or convenience sampling, the chances of errors are very high, it is most likely to affect the reliability and validity of this method.