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7/28/2019 Notes RM Chapter 11
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Chapter 11
Sampling
The nature of sampling:
- Population:Its the whole from which the researcher is going to drive a part known as asample.
- Population Element: a unit in the population- Population Frame: List of the whole (all population elements), official type of
document.
- Sample: a unit of the element- Subject: a unit of the sample
Example:
- Research Topic: postgraduate students studyingMBA in greater Cairo- Population: any institution or university giving MBA degree, the whole.- Population Element: Eslsca, unit of the whole- Sample: Class in Eslsca, unit of the element- Subject: students in the class, unit of the sample- Population Frame: List of all institutions all universities granting MBA.
In probability sampling:
- Researcher should provide a complete list of the population elements in the populationframe.
- If researcher is ready with population frame, then he can work probability sampling;since everybody is involved, this means that everybody has got an equal chance of being
chosen.
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Appropriate sample size:
- In quantitative: a minimum number of a good representative, samples is required,number is calculated through an equation proportional of the total size of population.
A representative sample: a sample that represents and keeps the characteristics of the
population (gender and age diversity).
- In qualitative: sample saturation is the goal, researcher doesnt have a minimum or amaximum number.
Steps:
1- Target population: Who is the appropriate person who is eligible to fill thequestionnaire? Is it women only or men only or middle managers.
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2- Parameters of interest: Research hypothesis tell exactly the parameters of interest andwhat to ask the target population.
3- Sampling frame: its a list of the members included in a sample.4- Sampling method5- Sample Size:
In quantitative: a number is calculated through an equation proportional of the total
size of population.
In qualitative: sample saturation is the goal, researcher doesnt have a minimum or a
maximum number.
Restricted probability sampling Unrestricted random sampling- Researcher has some restrictions to
put into considerations.
- Researcher giving questionnaire towhoever without any restriction,
irrespective of age or gender, and ask
him to fill the questionnaire.
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Probability Nonprobability
- Unrestricted - Simple random sampling - Convenience sampling:whoever is available & willing
to participate will be part of
the sample.
- A case of sampling that youcant get hold of the total
population.
- RestrictedCertain
considerationsto meet
- Complex random1-Systematic: researcher knows
population elements and startpicking samples according to
specific order, i.e 1,3,5,7.
2-Cluster: is the most highlydefined sample.
3-Stratified: is dividing sampleinto no. of strata.
4-Double: It is surveying thesame person twice.
- Purposive sampling: there arecertain standards that make the
sample eligible to answer thequestions.
- Three types of purposivesampling:
1-Judgment: looking forsomeone specifically.
2-Quota: maintain certainsample size to be sure that
sample is representative.
3-Snowball: ask participant torecommend another one.
- - Every and each one has equalopportunity of being chosen.
- We use it when we knowexactly the population.
- It generates more reliablefindings.
- Generalizable.
- When researcher dont knowwho the population is.
- Its about validity & notgeneralizability.
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Systematic: researcher knows every element in the population elements and start picking
samples according to specific order, i.e 1,3,5,7.
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Stratified sampling in research= market segment in marketing
It is dividing sample into number of strata, each strata has got certain characteristics. i.e: class is
the strata, stratum will be:
- Stratum 1: top performers- Stratum 2: poor performers.
People within the same stratum are having homogeneity
From one stratum to another, there is a case of heterogeneity.
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Cluster sampling:
- It is the complete opposite of stratified sampling.- It is the most highly defined sample ever.- Sample is divided to clusters: cluster 1 & cluster 2
People within cluster 1 are heterogenous. From cluster 1 to cluster 2, there is homogeneity.
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Very Important slide.
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Double Sampling:
1. It is surveying the same person twice.i.e: a researcher has done a survey about student satisfaction, 20 students participated,however, 5 of them gave deep answers to the questions, the researcher resurvey them
and that would be double sampling
2. A sample of the sample, same scope but different questions
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Area sampling = geographic sampling
Mobinil, Vodafone and Etisalat are helping with area sampling.
Area sampling is used extensively in marketing research.
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