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Chapter 1: Introduction andGraphical Displays
DisadvantagesofaSystematicSample
The sampled elements may fit somepatternof selection.
It is less random thanwhen a sample is obtained by just a simple
random sampling procedure.
ConvenienceSample
Convenience sampling procedure is sometimes called
grab
or
opportunity
sampling. It is amethodof choosing items in anunstructuredmanner from
the population. Although it is almost impossible to treat in a rigorous
manner, it is the sampling proceduremost commonly used inmany practical
situations. Forexample, when researchers are studying how a particular
illness will react to a certain drug, the researcherwill conveniently use
patients with such illness.
Definition:ConvenienceSample
A convenience sample is obtained byselecting the samplewhich is most
convenient to the researcher.
There are someadvantages and disadvantages of selecting a convenience
sample.
AdvantagesofaConvenienceSample
It is very simple touse.
It is usually cheap touse in order toobtain a sample.
DisadvantagesofaConvenienceSample
The sampled elements usually donot result in a representative sample
of the population.
The inferences from this sampling procedureare less conclusive.