Quantitative%20Research%201:%20Sampling%20and%20Surveys

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Quantitative Research 1Sampling and Surveys

• Dr N L Reynolds

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Quantitative Research 1

• Lecture objectives
• To provide an overview of the sampling process
• To understand how sample sizes are determined
• To examine the impact of sampling on the analysis
  of quantitative data
• To look at what is needed for good descriptive
  research
• To highlight some issues and stages in the design
  of a research instrument

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Importance of Sampling and Surveys

• Sampling is the who of research brilliant
  questions (or observations) of the wrong sample
  equals research that does not fulfill its
  research objectives
• Surveys provide a means to ask large samples the
  same set of questions efficiently and
  effectively. They allow populations to be
  described.
• Research instruments provide a template for data
  collection well designed research instruments
  make the researchers job easier

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Key Issues

1. How do should we go about sampling?
2. How can sampling affect the data?
3. What is a survey?
4. How is a good (quantitative) research instrument
   designed?

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Key Issue 1The sampling process

1. Define the population of interest and, if
   possible, identify the sampling frame(s)
2. Determine the sampling objectives
3. Select the sampling procedure
4. Determine the sample size
5. Select the sampling elements
6. Collect the data from the designated elements

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Key Issue 1Sampling procedures

• Non-probability methods
• Convenience sampling
• Judgment sampling
• Snowballing
• Quota sampling

• Probability methods
• Simple random sampling
• Stratified sampling
• Cluster sampling

NB Estimation of sampling error requires a
probability sample
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Key Issue 1Determining sample size

• Practical
• Resources available (time, money, personnel)
• Historical
• Research objectives
• Planned analysis
• Statistical
• Sampling distribution of the statistic
  (homogeneity of the population), precision,
  confidence

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Key Issue 1Calculating sample size

• Using standard deviations
• Using proportions
• n sample size
• Z desired confidence interval (within 1, 2 or 3
  standard deviations of the mean on normal curve)
• E acceptable level of sampling error
• s standard deviation in the population
• P proportion in the population

n Z2 s2 E2
n Z2 P (1-P) E2
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Key Issue 2Impact of sampling on analysis

• Non-parametric and parametric tests
• Requirements of specific data analysis technique
• T-tests, multivariate regression, factor
  analysis, conjoint analysis,
• Managerial confidence in the results

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Key Issue 3What is survey research?

• Direct communication with the respondents
  (sample)
• Collecting data using a research instrument
  (usually a questionnaire)

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Key Issue 3Survey research methods

• The Research Instrument
• Level of structure of the research instrument
• Level of disguise concerning the subject of the
  research
• Basic Data Collection Methods
• Face-to-face
• Telephone

• Mail
• Electronic

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Key Issue 3Which method should be used?

• Absolute variable costs
• Speed of responses
• Sample issues
• Response rates
• Data quality
• Reliability validity

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Key Issue 4Questionnaire Design

1. Develop question topics
2. Select question and response formats
3. Select question wording
4. Determine sequence
5. Design layout and appearance
6. Pilot test
7. Undertake survey

End
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Key Issue 4Individual Questions

• Is the question necessary?
• Several questions or just one?
• double questions
• Can respondents answer the question?
• Will respondents answer the question?
• Is the question clear and unbiased?
• type of language used
• ambiguity in item wording
• leading the respondent to a particular response

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Sampling And Surveys Their contribution to your
dissertation

• All will use samples of some sort people,
  organisations, countries, events, things (papers)
  having knowledge of the sampling process
  ensures your ability to justify how you have
  sampled
• All will read papers where sampling has been
  used being able to critique the sampling will
  contribute to the critical analysis of the study
  concerned.
• Most will use a research instrument for their
  dissertation for interviews, for focus groups,
  for surveys knowing how to design the
  instrument well will contribute to the quality of
  the research conducted
• All will read papers that use a research
  instrument of some kind being able to critique
  the design will contribute to the critical
  analysis of the study described