Simple Random Sampling

Programme: Master of Library & Information Science
Course: MLIS-09: Research Methodology
Target group: Master's students & Research Scholars



 Simple Random Sampling

                                                  

            In this method, each and every unit of the population has an equal chance of being selected in the sample. Selection of a unit is independent of other units in the sample.

            A number of techniques are used to select a random sample. Lottery method is the simplest method where all the units are numbered on identical slips of paper. All the sips are folded and mixed in a drum thoroughly. Required numbers of slips are drawn from the drum blindfold.
           
Random sample can also be selected by constructing lists of all the units by assigning numbers 1,2,3 … and selecting the units from the random number tables constructed for the purpose.  

            Another method of selecting the random sample is selecting from the sequential lists. In this method the names are arranged serially according to alphabetical, geographical or in serial order. Then out of the list every 10th or any number of cases may be selected.

Merits and Demerits of Simple Random Sampling:

The advantages of this method are –
1.      It is a more scientific method and eliminates personal bias of the researcher
2.      No knowledge of the characteristics of the population is required
3.      Sample drawn is more representative of the universe.
4.      Accurate results can be expected
5.      Very simple to follow and it saves time, money and labour.

The random sampling method has certain difficulties and limitations. These are –

1.      This method requires complete lists of the population. For some types of enquiries, lists may not be available. In such cases this method cannot be used.
2.      If the data is to be collected from a wider geographical area, then this method is difficult to use as it consumes more time and requires lot of money.
3.      If the sample size is too small, then it may not be representative of the population.

Activity

1. There are 60 bright students in a school who wanted to participate in inter school quiz competition. The principal wants to select only 10 members from them. Think if Simple Random Method is useful to select the required 10 students. List out any 3 reasons why this method is applicable.

1. __________________
2.___________________
3.___________________