MKC2500 Lecture Notes - Lecture 11: Quota Sampling, Convenience Sampling, Stratified Sampling
18 Jun 2018
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ETC2500 Notes
Non Probability Sampling Techniques
Convenience Sampling
• Convenience sampling attempts to obtain a sample of convenient elements.
Often, respondents are selected because they happen to be in the right place
at the right time.
o Use of students, and members of social organizations
o Mall intercept interviews without qualifying the respondents
o Department stores using charge account lists
o “People on the street” interviews
Judgmental Sampling
• Judgmental sampling is a form of convenience sampling in which the
population elements are selected based on the judgment of the researcher.
o Test markets
o Purchase engineers selected in industrial marketing research
o Bellwether precincts selected in voting behavior research
o Expert witnesses used in court
Quota Sampling
• Quota sampling may be viewed as two-stage restricted judgmental sampling.
o The first stage consists of developing control categories, or quotas, of
population elements.
o In the second stage, sample elements are selected based on
convenience or judgment.
Snowball Sampling
• In snowball sampling, an initial group of respondents is selected, usually at
random.
o After being interviewed, these respondents are asked to identify others
who belong to the target population of interest.
