16
© 2013 Cengage Learning. All Rights Reserved. May
not be scanned, copied or duplicated, or posted to a
publicly accessible website, in whole or in part.
Sampling Designs and
Sampling Procedures
Chapter 16
Sampling Designs and Sampling
Procedures
Business Research Methods 9e
Zikmund
Babin
Carr
Griffin

LEARNING
OUTCOMES
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
1. Explain reasons for taking a sample rather
than a complete census
2. Describe the process of identifying a target
population and selecting a sampling frame
3. Compare random sampling and systematic
(nonsampling) errors
4. Identify the types of nonprobability
sampling, including their advantages and
disadvantages
16-2

LEARNING
OUTCOMES
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
5. Summarize the advantages and
disadvantages of the various types of
probability samples
6. Discuss how to choose an appropriate
sample design, as well as challenges for
Internet sampling
16-3

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Changing Pocketbook Problems for
Today’s Families
16-4
•Each quarter, the Gallup
Corporation develops a
representative sample
of approximately 1,000
U.S. adults to capture
public perceptions of
financial concerns of
the family.
•The most important
problem facing families
can often change over
time.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–5
Sampling Terminology
•Population (universe)
• Any complete group of entities that share some
common set of characteristics.
•Population Element
• An individual member of a population.
•Census
• An investigation of all the individual elements that
make up a population.
•Sample
• A subset, or some part, of a larger population.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–6
Why Sample?
•Pragmatic Reasons
• Budget and time constraints.
• Limited access to total population.
•Accurate and Reliable Results
• Samples can yield reasonably accurate
information.
• Strong similarities in population elements makes
sampling possible.
• Sampling may be more accurate than a census.
•Destruction of Test Units
• Sampling reduces the costs of research in finite
populations.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Finding Out about Work Is a Lot of
Work!
16-7
•The U.S. Census
Bureau and the Bureau
of Labor Statistics
conduct the Current
Population Survey
(CPS).
•Uses a scientifically
derived panel sample
of 60,000 households.
•Sophisticated and
detailed.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
EXHIBIT 16.1 Stages in the Selection of a Sample
16–8

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–9
Practical Sampling Concepts
•Defining the Target Population
• What is the relevant population?
• Whom do we want to talk to?
◗ Population is operationally defined by specific and
explicit tangible characteristics.
•The Sampling Frame
• A list of elements from which a sample may be
drawn; also called working population.
• Sampling Frame Error
◗ Occurs when certain sample elements are not listed or
are not accurately represented in a sampling frame.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
EXHIBIT 16.2 Mailing List Directory Page
16–10

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–11
Practical Sampling Concepts (cont’d)
•Sampling services (list brokers)
• Provide lists or databases of the names,
addresses, phone numbers, and e-mail
addresses of specific populations.
• Reverse directory
◗ A directory similar to a telephone directory except
that listings are by city and street address or by
phone number rather than alphabetical by last
name.
•International Research
• Availability of sampling frames varies
dramatically around the world.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–12
Sampling Units
•Sampling Unit
• A single element or group of elements subject
to selection in the sample.
• Primary Sampling Unit (PSU)
◗ A unit selected in the first stage of sampling.
• Secondary Sampling Unit
◗ A unit selected in the second stage of sampling.
• Tertiary Sampling Unit
◗ A unit selected in the third stage of sampling.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–13
Random Sampling and Nonsampling Errors
•Random Sampling Error
• The difference between the sample result and the
result of a census conducted using identical
procedures.
• A statistical fluctuation that occurs because of
chance variations in the elements selected for a
sample.
•Systematic Sampling Error
• Systematic (nonsampling) error results from
nonsampling factors, primarily the nature of a
study’s design and the correctness of execution.
◗ It is not due to chance fluctuation.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–14
•Less than Perfectly Representative
Samples
• Random sampling errors and systematic
errors associated with the sampling process
may combine to yield a sample that is less
than perfectly representative of the
population.
Random Sampling and Nonsampling
Errors (cont’d)

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
EXHIBIT 16.3 Errors Associated with Sampling
16–15

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–16
•Probability Sampling
• A sampling technique in which every member
of the population has a known, nonzero
probability of selection.
•Nonprobability 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.
Probability versus Nonprobability Sampling

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
How Much Does Your Prescription Cost?
It Depends on Who You Buy It From
16-17
•A survey of 200 pharmacies
found that prices for the
same prescription could
vary as much as $100!

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–18
Nonprobability Sampling
•Convenience Sampling
• Obtaining those people or units that are most
conveniently available.
•Judgment (Purposive) Sampling
• An experienced individual selects the sample based
on personal judgment about some appropriate
characteristic of the sample member.
•Quota Sampling
• Ensures that various subgroups of a population will
be represented on pertinent characteristics to the
exact extent that the investigator desires.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
American Kennel Club Tries to Keep Pet
Owners out of the Doghouse
16-19
•The American Kennel
Club (AKC) used quota
sampling in a Dog
Ownership Study.
•Sampled 500 dog
owners and 500 non-
owners.
•Dog owners described
themselves as more
laid-back and happy
than non-owners.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–20
Nonprobability Sampling (cont’d)
•Possible Sources Of Bias
• Respondents chosen because they were:
◗ Similar to interviewer
◗ Easily found
◗ Willing to be interviewed
◗ Middle-class
•Advantages of Quota Sampling
• Speed of data collection
• Lower costs
• Convenience

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–21
Nonprobability Sampling (cont’d)
•Snowball Sampling
• A sampling procedure in which initial
respondents are selected by probability
methods and additional respondents are
obtained from information provided by the
initial respondents.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–22
Probability Sampling
•Simple Random Sampling
• Assures each element in the population of an equal
chance of being included in the sample.
•Systematic Sampling
• A starting point is selected by a random process and
then every nth number on the list is selected.
•Stratified Sampling
• Simple random subsamples that are more or less equal
on some characteristic are drawn from within each
stratum of the population.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–23
•Proportional Stratified Sample
• The number of sampling units drawn from
each stratum is in proportion to the
population size of that stratum.
•Disproportional Stratified Sample
• The sample size for each stratum is
allocated according to analytical
considerations.
Proportional versus Disproportional
Sampling

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
EXHIBIT 16.4 Disproportional Sampling: Hypothetical
Example
16–24

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–25
Cluster Sampling
•Cluster Sampling
• An economically efficient sampling technique in
which the primary sampling unit is not the
individual element in the population but a large
cluster of elements.
• Clusters are selected randomly.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Who’s at Home? Different Ways to
Select Respondents
16-26
•Methods of generating
representative samples:
• Full enumeration
• Kish method
• Who had last birthday?

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–27
Multistage Area Sampling
•Multistage Area Sampling
• Involves using a combination of two or more
probability sampling techniques.
◗ Typically, geographic areas are randomly selected in
progressively smaller (lower-population) units.
◗ Researchers may take as many steps as necessary to
achieve a representative sample.
◗ Progressively smaller geographic areas are chosen
until a single housing unit is selected for
interviewing.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
EXHIBIT 16.6 Illustration of Multistage Area Sampling in
the United States
16–28

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
EXHIBIT 16.7 Geographic Hierarchy Inside Urbanized
Areas
16–29

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–30
What is the Appropriate Sample Design?
•Degree of accuracy
•Resources
•Time
•Advanced knowledge of the population
•National versus local project

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
New on Campus: Student Adjustment to
College Life
16-31
• Stress and tension can impact
students when they first arrive at
school.
• Students were surveyed when
they arrived and at the end of the
first year.
• It’s not good to engage in
negative coping behaviors or
have perfectionist tendencies.
• Better to be optimistic and
socially oriented.
• Used a panel approach to assess
change that occurred within a
sample of students over time.

© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16–32
Internet Sampling is Unique
•Website Visitors
• Internet surveys use unrestricted samples.
• May not be representative.
•Panel Samples
•Recruited Ad Hoc Samples
•Opt-in Lists