1. SAMPLING TECHNIQUES

2. SAMPLING
Procedure by which some members of a given population are selected as representatives of the entire population.

3. UNIVERSE
the larger group from which individuals are selected to participate in a study
SAMPLE
the representatives selected for a study whose characteristics exemplify the larger group from which they were selected

4. PURPOSE OF SAMPLING To gather data about the population in order to make an inference that can be generalized to the population
POPULATION
INFERENCE
SAMPLE

5. Process Of Sampling Define the Population Develop Sampling Frame
Select a Sampling Method
Determine Sample Size
Execute the Sampling Process

6. The Sampling Process Define the Population Develop Sampling Frame
Select a Sampling Method
Determine the Sample Size
Execute the Sampling Process

7. Sampling and representativeness
Sample
Sampling
Population
Target Population
Target Population  Sampling Population  Sample

8. Sampling Techniques Fixed Attributes Vs Vs Sequential Variables
Probability Vs
Non-probability
sampling

9. NON-PROBABILITY SAMPLING
Every element in the target population or universe [sampling frame] has equal probability of being chosen in the sample for the survey being conducted.
Scientific, operationally convenient and simple in theory.
Results may be generalized.
NON-PROBABILITY SAMPLING
Every element in the universe [sampling frame] does not have equal probability of being chosen in the sample.
Operationally convenient and simple in theory.
Results may not be generalized.

10. CLASSIFICATION OF SAMPLING TECHNIQUES
Sampling Methods
Probability Sampling Methods
Simple Random Sampling
Stratified Random Sampling
Systematic Random Sampling
Multistage Random Sampling
Cluster Sampling
Area Sampling
Non-probability Sampling Methods
Convenience Sampling
Judgment Sampling
Quota Sampling
Other Sampling Methods

11. SIMPLE RANDOM SAMPLING
Simple random sampling is a method of probability sampling in which every unit has an equal non zero chance of being selected for the sample.
Methods of selecting random sample:
Lottery Method
Tables of Random Numbers

12. STRATIFIED RANDOM SAMPLING
Stratified random sampling is a method of probability sampling in which the population is divided into different subgroups and samples are selected from each of them.
Steps:-
All units of population are divided into different stratas in accordance with their characteristics.
Using random sampling, sample items are selected from each stratum.

13. Systematic Random Sampling or Quasi-Random Sampling
Systematic random sampling is a method of probability sampling in which the defined target population is ordered and the 1st unit of sample is selected at random and rest of the sample is selected according to position using a skip interval (every Kth item)
K = N n
Where, K = Sampling/ Skip interval
N = Universe/ Population Size
n = Sample Size

14. MULTISTAGE RANDOM SAMPLING
Used in large scale investigations
First stage- preparation of large sized sampling units
Randomly selecting a certain number
Second stage- Another list prepared from them
Sub-samples drawn by random sampling

15. CLUSTER SAMPLING Steps :-
The process of randomly selecting intact groups, not individuals, within the defined population sharing similar characteristics
Steps :-
Defined population is divided into number of mutually exclusive and collectively exhaustive subgroups or clusters
Select an independent simple random sample of clusters.

16. Area Sampling
One special type of cluster sampling is called area sampling, where pieces of geographical areas such as districts, housing blocks or townships are selected.
Area sampling could be one-stage, two-stage, or multi-stage.
Generally used by Govt. agencies and agricultural statistics.

17. Non-probability Sampling Methods

18. Convenience sampling
the process of including whoever happens to be available at the time…called “accidental” or “haphazard” sampling.

19. Purposive sampling
the process whereby the researcher selects a sample based on experience or knowledge of the group to be sampled…called “judgment” sampling

20. Quota sampling
the process whereby a researcher gathers data from individuals possessing identified characteristics and quotas

21. Other Non-probability Sampling Methods
Intensity sampling: selecting participants who
permit study of different levels of the research topic
Homogeneous sampling: selecting participants who
are very similar in experience, perspective, or outlook
Criterion sampling: selecting all cases
that meet some pre-defined characteristic
Snowball sampling relies upon respondent
referrals of others with like characteristics

22. Factors to Consider in Sample Design
Research objectives
Degree of accuracy
Resources
Time frame
Knowledge of
target population
Research scope
Statistical analysis needs

23. THANK YOU