1. Marketing 6 Chapter 14
Sampling Fundamentals
Reported by:
Franklin K. Go
Raymond A. Gonzales
Angelo R. Cantor

2. Learning Objectives
1. Distinguish between a census and a sample.
2. Know the difference between sampling and
non-sampling errors.
3. Learn the concept of sampling process.
4. Describe probability and non-probability
sampling procedures.
5. Determine sample size with ad-hoc methods.
6. Learn to deal with non-response problems.
7. Understand sampling in international context.

3. Sample or Census
• A researcher is interested in the
characteristics of the population wherein
his potential target market may reside.
The respondents are asked to input
necessary information through surveys
called census.

4. When a Census is Appropriate
• A census is appropriate if the sample size
is small. Every individual may be included
in the population.

5. When a Sample is Appropriate
• A sample is appropriate if the population is
large, the time allotted in obtaining the
information from the population is long and
the cost is high.

6. Error in Sampling
Error in sampling occurs if there is a gap
between the true value and the observed
value of the variable interest of the
population.
• Sampling Error occurs if the error lies in
the sample parameter and the sample
statistics because of sampling.
• Non-sampling Error occurs if the error lies
in the population.

7. Sample Process
Factors that should be considered when the
decision to use a sample is made:
• Various steps included in sampling
• Major activities with sampling process

8. Various steps included in sampling

9. Major activities with sampling
process
1. Identify the target population.
2. Determine the sampling frame.
3. Resolving the Differences.
4. Selecting a sampling procedure.
5. Determining the relevant sample size.
6. Obtaining information from respondents.
7. Dealing with the non-response public.
8. Generating information for decision-making
purposes.

10. Determining the Target Population
The following should be considered in determining
the target population:
1. Look to the research objectives
2. Consider alternatives
3. Know your market
4. Consider the appropriate sampling unit
5. Specify clearly what is excluded
6. Don’t overdefine
7. Should be reproducible
8. Consider convenience

11. Determining the Sampling Frame
Tasks to do in determining the sample
frame:
1. Create lists
2. Create lists for telephone interviewing
3. Dealing with population sampling frame
difference

12. Determining the Sampling Frame
Three types of problems when dealing with
population sampling frame difference:
1. Subset problem
2. Superset problem
3. Intersection problem

13. Selecting a Sampling Procedure
• Select between Bayesian Sampling
Procedure and Traditional Sampling
Procedure.
• Decide whether the sample may have a
replacement or not.

14. Probability Sampling
Probability sampling involves four
considerations:
1. The target population must be specified.
2. The methods for selecting sample needs
to be developed.
3. The sample size must be determined.
4. The non-response problem must be
addressed.

15. Selecting the Probability Sample
Methods used to select a probability sample:
• Simple Random Sampling
• Accuracy Cost Trade-off
• Stratified Sampling
• Proportional Stratified Sampling
• Directly Proportional Stratified Sampling
• Inversely Proportional Stratified Sampling
• Disproportional Stratified Sampling
• Cluster Sampling
• Systematic Sampling

16. Multistage Design
Cities in Ajax Country
City Population Cumulative Population
Concorde 15000 1-15000
Mountain View 10000 15001-25000
Filmore 60000 25001-85000
Austin 5000 85001-90000
Cooper 2000 90001-92000
Douglas 5000 92001-97000
Rural Area 3000 97001-100000

17. Non-probability Sampling
The following are stages where non-
probability sampling is used:
1. Exploratory stage of a research project
2. Pretesting a questionnaire
3. Dealing with homogeneous population
4. When researcher lacks statistical knowledge
5. When operational ease is required

18. Non-probability Sampling
The following are the four types of non-
probability sampling:
1. Judgment
2. Snowball
3. Convenience
4. Quota

19. Determining the Sample Size
How large should the sample be?

20. Non-response Problems
The following are reasons why some of the
populations become non-respondents:
1. Refuse to respond
2. Lack of ability to respond
3. Not at home
4. Inaccessible

21. What can be done about the non-
response problems?
1. Improve the research design to reduce
non-responses.
2. Repeat the contact one or more times to
reduce non-responses (callbacks).
3. Attempt to estimate the non-response
bias.

22. Shopping Center Sampling
Shoppers are intercepted and interviewed
personally or through surveys. This
method is called store-intercept interviews.

23. Shopping Center Sampling
Shopping Center Selection
• Selecting a shopping center is essential
because the respondents will be those
who live in the nearby area. The standard
of living of the neighborhood will affect
how the sampling will take place and the
types of samples that will be obtained.

24. Shopping Center Sampling
Sample Locations within a Center
• This is randomly selecting samples
through shopping center visits.

25. Shopping Center Sampling
Time Sampling
• Time segments are devised when
obtaining sample data because of the fact
that the time people go shopping vary
from one another.

26. Shopping Center Sampling
Sampling People versus Shopping Visits
• Researchers should ask the respondents
on how often they shop. The respondents
are weighted based on the frequency of
visits when getting the average.