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Overview of Chapter 10:
Examining Sampling Plans Chapter 10 introduces you to
the concept of sample selection for both
quantitative and qualitative studies. As in other
aspects of study design, sampling issues are
handled quite differently by researchers working
within different paradigms in terms of goals,
approaches, and criteria for evaluating sample
adequacy. With regard to quantitative
research, the chapter describes several types of
nonprobability and probability samples and offers
guidelines for assessing the quality of the
researcher's sampling approach. Detailed procedures
concerning the complex topic of sample size are not
discussed, but the point is emphasized that sample
sizes in quantitative studies should generally be
large, especially if the population is
heterogeneous with respect to the variables of
interest. The principles underlying a power
analysis are also described, and an example is used
to show that generally fairly large samples are
needed to adequately test research hypotheses. The
point is made, however, that size alone cannot
guarantee a good sample. A sample for a
quantitative study is good if it is
representative, and several factors--most
importantly, size, method of selection, response
rate, and subject attrition--determine a high
quality sample. The issues of representativeness of
a sample and the adequacy of sample sizes are
particularly important because many quantitative
nursing research studies have weak sampling
designs. Qualitative researchers
employ very different strategies and are guided by
different considerations than quantitative
researchers. The chapter describes several
alternative approaches that are used to enhance the
information richness of the data obtained in
a qualitative study. In a qualitative study, random
selection is not only not attempted, it is
eschewed. Sample size is also guided by the data
adequacy rather than by the need to achieve certain
statistical goals. Study
Chapter 10 in the
text, pages 231-156. Use the forum
for Questions for Instructor on Part 3 in
WebCT for Nurs
400A
or Nurs
400B
to post questions about things you don't understand
in Chapter 10. |