“Woah! It's like Spotify but for academic articles.”

Instant Access to Thousands of Journals for just $40/month

Get 2 Weeks Free

A nonparametric two-sample comparison for skewed data with unequal variances

A nonparametric two-sample comparison for skewed data with unequal variances For practical situations, the pure shift model is probably not very realistic, and it is thus important to assess the robustness of different tests against deviations from this model. It is well established that heteroscedasticity (unequal variances) is at least as deleterious for the properties of the Wilcoxon-Mann-Whitney (WMW) test as for the t -test [1] and that the Welch test should replace the t -test when distributions are approximately normal and variances unequal. It is also worth remembering that the WMW test does not share the asymptotic robustness properties of the t -test. In addition, unequal variance is not the only problem frequently encountered. Distributions can also be skewed, and the skewness of the two distributions may differ. Unfortunately, but not unexpectedly, even the Welch test is unable to maintain the nominal significance level when distributions are skewed [1] .</P>Stochastic simulation is a valuable tool to compare test properties under different conditions. Based on simulation studies, Neuhäuser [2] proposes that the modified or generalized Wilcoxon test by Brunner and Munzel (BM) [3] should be applied when it cannot be assumed that variances are equal and distributions symmetric. In such situations, Skovlund and Fenstad [1] have shown that http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Clinical Epidemiology Elsevier
Loading next page...
 
/lp/elsevier/a-nonparametric-two-sample-comparison-for-skewed-data-with-unequal-FCXrBuIppO

You're reading a free preview. Subscribe to read or print the entire article.

And millions more from thousands of peer-reviewed journals, for just $40/month

Get 2 Weeks Free

To be the best researcher, you need access to the best research

  • With DeepDyve, you can stop worrying about how much articles cost, or if it's too much hassle to order — it's all at your fingertips. Your research is important and deserves the top content.
  • Read from thousands of the leading scholarly journals from Springer, Elsevier, Nature, IEEE, Wiley-Blackwell and more.
  • All the latest content is available, no embargo periods.

Stop missing out on the latest updates in your field

  • We’ll send you automatic email updates on the keywords and journals you tell us are most important to you.
  • There is a lot of content out there, so we help you sift through it and stay organized.