What are the merits and demerits of Random Sampling method?
(i) Scientific Technique:
It provides a scientific technique of selecting the sample from a universe in which each unit of the universe has the equal chance of being included in the sample.
(ii) Less chance of Bias:
There is little chance of bias and prejudices of investigator to play and influence the selection of the sample.
(iii) Based on Probability:
This method is based on the theory of probability which is a mathematical concept and as such it is quite possible to determine the sample error under this method.
(iv) More Accuracy:
It is possible to lay down the degree of accuracy achieved' the investigation conducted by this method.
(v) Suitable for Large Numbers:
It is quite suitable in case of large sampling where the size of both the sample and the universe is very large.
(vi) Less dependence on detailed Information:
It does not depend very much upon the existence of detailed information about the universe for its effectiveness. .
(vii) Evaluation of Relative Efficiency:
It is possible to evaluate the relative efficiency of various sample designs when conducted under this method.
It is highly expensive and time taking.
(ii) Requires More Skill:
It needs a very high level of skill and experience on the; part of the investigators.
(iii) Irrelevant Items:
It allows certain irrelevant and unwarranted items to get into the sample by chance and thereby vitiate the results of the study and prevents certain relevant and vital items from being included in the sample.
(iv) It prevents the experts and conversant from exercising their best judgment and knowledge of the universe in selecting the samples.
(v) Unsuitable for Small Sampling:
It is not suitable in case of small sampling where the size of the sample to be drawn is very small for in that case the laws of statistical regularity and inertia of large numbers will not operate and the chance of leach item of the universe being included in the sample will not remain the same.