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That applies in a within-subjects study design, i.e., in a study where the same set of subjects undergo both of the conditions being compared. Specific methods for carrying out paired difference tests include the paired-samples t-test, the paired Z-test, the Wilcoxon signed-rank test [1] and others.
Non-parametric tests have the advantage of being more resistant to misbehaviour of the data, such as outliers. [7] They also have the disadvantage of being less certain in the statistical estimate. [7] Type of data: Statistical tests use different types of data. [1] Some tests perform univariate analysis on a single sample with a single variable.
From the t-test, the difference between the group means is 6-2=4. From the regression, the slope is also 4 indicating that a 1-unit change in drug dose (from 0 to 1) gives a 4-unit change in mean word recall (from 2 to 6). The t-test p-value for the difference in means, and the regression p-value for the slope, are both 0.00805. The methods ...
For two matched samples, it is a paired difference test like the paired Student's t-test (also known as the "t-test for matched pairs" or "t-test for dependent samples"). The Wilcoxon test is a good alternative to the t-test when the normal distribution of the differences between paired individuals cannot be assumed. Instead, it assumes a ...
In statistics, Welch's t-test, or unequal variances t-test, is a two-sample location test which is used to test the (null) hypothesis that two populations have equal means. It is named for its creator, Bernard Lewis Welch , and is an adaptation of Student's t -test , [ 1 ] and is more reliable when the two samples have unequal variances and ...
In particular cases, simpler tests like paired difference test, McNemar test and Cochran–Mantel–Haenszel test are available. When the outcome of interest is continuous, estimation of the average treatment effect is performed. Matching can also be used to "pre-process" a sample before analysis via another technique, such as regression ...
the value of T can be compared with its expected value under the null hypothesis of 50, and since the sample size is large, a normal distribution can be used as an approximation to the sampling distribution either for T or for the revised test statistic T−50. Using one of these sampling distributions, it is possible to compute either a one ...
The sign test is a statistical test for consistent differences between pairs of observations, such as the weight of subjects before and after treatment. Given pairs of observations (such as weight pre- and post-treatment) for each subject, the sign test determines if one member of the pair (such as pre-treatment) tends to be greater than (or less than) the other member of the pair (such as ...