Topic: How to choose research participants?

Presented By:

Name Registration No.

MD. Afiqul Islam 2009731031

Tipu Lal Datta 2009731044

Md.Ehteshamul Haque 2009731059

Anusuya Paul Ripa 2009731067

Group name: Ordinal

INTRODUCTION

In every research project researcher have to choose his participants and decide what types of people he need to contact. When researcher contact everyone in the population it is called census. But it is difficult to contact with every person in a research population. To overcome this problem researcher use sampling method.

WHAT IS SAMPLING?

Population: Any complete group of entities that share

common set of characteristics is called population.

Sample: A subject or same part of larger population.

Sampling: Sampling is a procedure that uses a small member of units of a given population as a basis for drawing conclusions about the whole population.

PopulationPopulation

SampleSample

REASONS FOR SAMPLING

Budget and time constraints

High degree of accuracy and reliability

More detailed information

Destructive nature of certain tests

Methods of sampling

Basically there are two types of sampling:

2. NON-PROBABILITY SAMPLING: A sampling technique in which units of the sample are selected on the basis of personal judgment or convenience; the probability of any particular member of the population being chosen is unknown.

1. PROBABILITY SAMPLING: A sampling technique in which every member of the population has a known, nonzero probability of selection.

Types of probability samplingSimple random sampling: This is a technique which ensures that each element in the population has an equal and independent chance of being selected for the sample.

Stratified Sampling: This is a technique which in which simple random subsamples are drawn from within different strata that share some common characteristic

Systematic Sampling: This is a technique which in which an initial starting point is selected by a random process, after which every nth number on the list is selected to constitute part of the sample

Cluster sampling: It is used when there are well-defined clusters (groups) within the population

Types of non-probability samplingConvenience sampling : Selecting participants that are easy to get or available and agree to participate

Judgment (purposive) Sampling: This is a sampling technique in which the business researcher selects the sample based on judgment about some appropriate characteristic of the sample members

Quota sampling: Establish subgroups to be included in the sample, then establish quotas for those individuals to be selected from each subgroup

Snowball Sampling: This is a sampling technique in which individuals or organizations are selected first by probability methods, and then additional respondents are identified based on information provided by the first group of respondents

Size of Sample

Sample size depends on the type and purpose of the research.

It tends to be general rule in quantitative research that the larger the sample the more accurate the results.

Statistical methods can be used to determine the sample size.

Sample size should take into account issues of non-response.

Conclusion

Every sampling method has some advantages and disadvantages. It is possible to use a mixture of sampling techniques within one project which may help to overcome some of the disadvantages found within different procedures.

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