3.1.6 Essentials of sampling
If the sample results are to have any worthwhile meaning, it is necessary that a sample possesses the following essentials:
i. Representativeness. A sample should be selected such that it truly represents the universe otherwise the results obtained may be misleading. To ensure representativeness the random method of selection should be used.
ii. Adequacy. The size of sample should be adequate, otherwise characteristic of the universe may be obtained is to less accuracy.
iii. Independence. All items of the sample should be selected independently of one another and all items of the universe should have the same chance of being selected in the sample. By independence of selection we mean that the selection of a particular item in one draw has influence on the probabilities of selection in any other draw.