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Trimmed means: comparison of independent samples (Yuen-Welch test)

Next selectTrimmed means
Next selectComparison of independent samples


The Yuen-Welch test is used to compare the trimmed means of two independent samples.

Required input

Yuen-Welch test - dialog box

Select the variables for sample 1 and sample 2. Differences will be calculated as Sample2−Sample1.

Caveat: if the two variables are the same, then the two filters must define distinct groups so that the same case is not included in the two samples.



The results windows displays the sample size, arithmecic mean and its 95% confidence interval, followed by the trimmed mean, the trimmed mean sample size and the 95% confidence interval of the trimmed mean for the 2 samples.

Yuen-Welch test

The report shows the difference between the trimmed means with its 95% confidence interval.

Next follow the test statistic t, the Degrees of Freedom (DF) and the two-tailed probability P. When the P-value is less than the conventional 0.05, the null hypothesis is rejected and the conclusion is that the two trimmed means do indeed differ significantly.

Yuen-Welch test - results

See Calculation of Trimmed Mean, SE and confidence interval for computational details.


See also

Recommended book

Book cover

Introduction to Robust Estimation and Hypothesis Testing
Rand R. Wilcox

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