sampling techniques used in research

different sampling techniques used in research : simple random sampling, random sampling

1. Sampling techniques in research

2. Population is defined as the entire mass of observation, which is the parent group from which a sample is to be formed . Sample is defined as the aggregate of objects, person or elements, selected from the universe.

3. Sampling- The method of taking the sample is known as sampling.

4. Probability sampling

5. Random sampling is applied when the method of selection assures each individual element in the universe an equal chance of being chosen.

6. Disadvantages

7. Methods of random sampling

8. Stratified sampling - When the population is divided into different strata then samples are selected from each stratum by simple random sampling or by regular interval method we call it as stratified random sampling method.

9. Disadvantages

10. Systemic sampling - This sampling is obtaining a collection of elements by drawing every nth person after that; n is a number termed as sampling interval.

11. Advantages Easy to use Disadvantages Over representation of several groups is greater.

12. Cluster Sampling- The whole population is surveyed and such areas are located wherein elements are seen clustering themselves and sample is selected from such clusters and they reflect all characteristics of the Universe.

13. Advantages

14. Disadvantages

15. Multi stage sampling sample is selected in various stages but only last sample is studied.

16. Advantages Good representative of population Improvement of other sampling methods Disadvantages Difficult and complex method

17. Non probability Sampling - One cannot estimate beforehand the probability of each element being included in the sample. It also does not assure that every element has a chance of being included.

18. Non probability sampling

19. Incidental or Accidental sampling means selecting the units on basis of easy approaches.

20. In Convenience method , the investigator selects certain items are to his convenience. No pre planning is necessary for the selection of items.

21. Advantages Easy method Economical

22. Purposive sampling- The selection of elements is based upon the judgement of the researcher, the purposive sampling is called judgement sample

23. Quota sampling:- In the quote sampling the interviewers are instructed to interview a specified number of persons from each category.

24. Technique Strength Weakness Probability Simple Random Sampling Easily understood, results projectable Expensive , assurance of representative Stratified sampling Include all important sub populations Expensive, Difficult to select relevant stratification variables Systemic sampling Increase representativeness Can decrease representative Cluster sampling Easy to implement, cost effective Difficult to interpret results Non probability Convenience sampling Least expensive, least time consuming. Quota sampling Sample can be controlled for certain characteristics Bias, no assurance of representative

25. Choosing non Probability vs. Probability sampling Conditions favouring the use of Factors Non probability sampling Probability sampling Nature of research Exploratory Conclusive Relative magnitude of sampling and non sampling errors Non sampling errors are larger Sampling errors are larger Variability in the population Homogeneous Heterogeneous Statistical consideration Unfavourable Favourable Operational considerations Favourable Unfavourable