# Quantitative%20Research%201:%20Sampling%20and%20Surveys - PowerPoint PPT Presentation

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

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### Quantitative Research 1: Sampling and Surveys Dr N L Reynolds – PowerPoint PPT presentation

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

1
Quantitative Research 1 Sampling and Surveys
• Dr N L Reynolds

2
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

3
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

4
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?

5
Key Issue 1 The 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

6
Key Issue 1 Sampling 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
7
Key Issue 1 Determining 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

8
Key Issue 1 Calculating 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
9
Key Issue 2 Impact 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

10
Key Issue 3 What is survey research?
• Direct communication with the respondents
(sample)
• Collecting data using a research instrument
(usually a questionnaire)

11
Key Issue 3 Survey 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

12
Key Issue 3 Which method should be used?
• Absolute variable costs
• Speed of responses
• Sample issues
• Response rates
• Data quality
• Reliability validity

13
Key Issue 4 Questionnaire 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
14
Key Issue 4 Individual 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

15
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