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Sampling
Sampling is an important aspect of the experimental research design and must be correctly initiated because where there is more than just one condition in the experiment one group is used as a control group whereas the others are tested under the experimental conditions. (Experiment Resources, 2009) Group samples can be determined in several ways including:
(1) Randomization;
(2) Quasi randomization; and
(3) Pairing. (Experiment Resources, 2009)

These sampling methods are stated to be the most common among sampling methods which are used. At the time the experiment in constructed the researcher often adjust the sample size to reduce the changes of random sampling errors. (Experiment Resources, 2009, paraphrased) Factors that impact the research design chosen include those such as time, money, ethics and measurements problems. The design of the experiment is critical for the validity of the results. (Experiment Resources, 2009) Typical designs in experiments include:
(1) Pre-test: for the purpose of checking as to whether the groups are different prior to the experiment and known to sometimes influence the effect
(2) Post-test: Measurement of the effect(s)......

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