1. Business Research Methods
Types of Sampling

2. Sampling Methods/ Designs
Types of Sampling
Probability Sampling Methods
Simple
Stratified
Cluster
Multi-stage
Non-Probability Sampling Methods
Convenience
Judge
ment
Quota
Snowball

3. Probability Sampling Method
Sample units selected at Random
Equal chance for being selected as representative
Provide unbiased information
Independent and Impartial selection of Sample
Based on the theory of Probability

4. 1.A. Simple Random Sampling
Selection of sample at random
Useful for telephone/ mail survey
Methods:
Lottery Sampling (no. selected between 1 & 10)
e.g. 3,13,23,33,43,53 and so on
Sampling by the use of random number tables
Arranged numerically for selection

5. 1. B. Stratified Sampling Proportional Random Sampling
Population> Groups> Sample
Basis of Group Formations
Geographical Area
Size of Household
Income
An improvement over simple random sampling because the group is tried to be made more representative
E.g All Students>Year>Sample

6. 1. C. Cluster Sampling Group wise inclusion in the sample
Individual units are clubbed together
E.g. Total universe > Groups
In this case , the sample under study is a group selected out of the universe
Savings in costs & time
Greater danger of over/ under representation

7. 1.D. Multi- Stage Sampling
Sampling is done at multiple stages
Applicable in big enquiries extending to a large geographical area , say, the whole country
E.g. Working efficiency of nationalized banks
India > State wise > District wise
Flexible
Time & Effort
Large number in a given cost
Surveys of underdeveloped areas of a country

8. Non-Probability Sampling
Purposive selection
Based on convenience & judgement of researcher
Subjective, by the researcher himself
Sample selected may not be the representative of the entire universe
Less cost, less time, Little statistical application

9. 2.A. Convenience Sampling
Importance to the convenience of Researcher
Easily accessible, readily available, easily measurable samples are selected
Accidental Sampling
Likely to be biased
Examples – Interviewing respondents at public places
Advantages
Disadvantages
Pretesting
Non representative
Tension free researcher
No equal chance
Convenience to Researcher
Cannot rule out bias of respondents

10. 2.B. Judgement Sampling
Purposive Selection of sample as per the expert judgement of the researcher
Expert in the subject of research must be selected
E.g. To study the effect of promotion activities, a marketing expert may be appointed for sampling purpose & further research

11. 2.C. Quota Sampling Universe > Identical Groups > Sample
Size of the sample , decided by the researcher
Investigators are given full freedom to select sample from the given quota of sample items
Selection is as per their convenience
Quick & easy
Economical
Errors , due to preferences & prejudices of the researcher

12. 2.D. Snowball Sampling
Sample selected and asked to select the further sample
One respondent being used to generate the names of others is snowball sampling
Networking for finding out respondents of some rare type
Small pool of initial infromants> Social Networks > Eligibility criteria > Contribute
Advantages
Disadvantages
Low Cost
Community Bias
Locate hidden population
Vague sample size
Locate people of a specific population
Little Control

13. Distinction – Probability v/s Non-Probability Sampling
Equal Chance
Systematic & Modern
Controlled Objectively
Mechanical & Mathemetical Process
Selection by chance
Probability Sampling
No equal opportunity
Traditional, outdated
Subjective
Mental Process
Selection by choice
Non Probability Sampling

14. Thank-You