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Table of Contents Statistical Tests Means Paired Experiments | |
See also: hypothesis testing, survey on statistical tests, comparing means, distribution calculator |
Assumption: the distribution of the differences is normal and the differences are a random sample.
The paired difference experiment is often more powerful, since it can eliminate differences in the samples that increase the total variance, s^{2}. When the comparison is made between groups (of similar experimental units), it is called blocking. The paired difference experiment is a simple example of a randomized block experiment.
NOTE: The blocking has to be done before the experiment is performed.
When the normality assumption is not fulfilled, one can use the non-parametric
Wilcoxon sign rank test for paired difference designs.
Last Update: 2005-Jul-16