In a school suppose there are 20 classes of 50 students each and if you take the exam of 1 student only out of those 50 students instead of taking exams of all 50 students so as to check the intelligence level of students of the whole school is called sampling. Sampling is the process by which sample is collected from a group or population and on the basis of that sample analysis about that data is made. In order to understand more about it, one should look at the advantages and disadvantages of sampling.
Advantages of Sampling
Saving of Money
The biggest advantage of sampling is that it helps an individual or company in saving a lot of money because imagine the cost involved if some data has to be collected from each and every member of the population. In simple words, if it takes $10000 for collecting data of whole group or population than it will take $500 to $1000 only for collecting data through sampling which results in the work of data collection being completed in one-tenth of the budget of an individual or company.
Another benefit of sampling is that it saves lot of time for an individual or company because suppose a company is taking survey which has 5 questions and for each question the participant take 2 minutes which implies 10 minutes of time for each participant now if company has to take survey of 1000 participants than it will take 10000 minutes for survey to complete. However, if the company adopts sampling process and asks only 100 participants then it will take only 1000 minutes and hence company will able to save valuable time due to sampling process and that time can be used for other productive things.
Only Way Out
Sampling is the only option if the population or group from which data is to be collected is very high because it is not practical as well as feasible to collect data from the whole population. Hence for example, if one has to know the literacy rate of big countries like India and China than sampling is the only way out due to the extremely large population of these countries.
Disadvantages of Sampling
No Complete Picture
The biggest disadvantage of sampling is that it may not present the complete picture, hence for example if in the above case if all students are above average in the sample than that result will be biased and it will show that all students are meritorious which is not the case and it has happened due to wrong selection of sample.
Another disadvantage of sampling is that chances of sampling being biased are there as the person who is taking the sample may select only those samples which result in an outcome of that result which the person taking the sample wants. Hence for example, if in the above example if the person wants to improve the image of school or college then he or she will select only good students for exams so that results are good which in turn will result in improvement of the image of the school or college.
Size of Sample
Another problem which comes with sampling is that size of the sample is a tricky thing because one never knows how much size will be the true representation of the whole population. Hence for example in above case whether to take 1 student from each class or take 2 students or take 3 students so as to have clear idea about the intelligence of students is a dilemma which will be always there in the minds of people doing sampling.
As one can see from the above that sampling has pros, as well as cons and any individual or company thinking of doing sampling for data collection, should carefully read above points and then take the decision whether they want to adopt sampling for data collection or not.