McElduff F, Cortina-Borja M, Chan SK, Wade A. When t-tests or Wilcoxon-Mann-Whitney tests won’t do. Adv Physiol Educ 34: 128–133, 2010; doi:10.1152/advan.00017.2010.—t-Tests are widely used by researchers to compare the average values of a numeric outcome between two groups. If there are doubts about the suitability of the data for the requirements of a t-test, most notably the distribution bei...

Rosette formation in 154 fresh Plasmodium falciparum isolates from Kenyan children with mild (n = 54), moderate (n = 64), or severe (n = 36) malaria was studied to determine whether the ability to form rosettes in vitro is correlated with malaria severity. There was a wide distribution of rosette frequencies within each clinical category; however, a clear trend towards higher rosette frequency ...

Invasive ductal carcinomas with a non-invasive component (IDC-DCIS) are classified as a group of invasive breast carcinomas, together with pure invasive ductal carcinomas of the breast (IDC). MicroRNA-21 (miR-21) has been characterized as a factor of breast cancer invasiveness, however the difference in miR-21 expression levels between IDCDCIS and pure IDC tumors and the correlations with stand...

In this paper two nonparametric tests for monotonic trend detection are compared with respect to their power and accuracy. The importance of comparing powers at equal empirical signiicance levels rather than nominal levels, is stressed. Therefore, an appropriate graphical method is presented. The eeect of the sampling frequency is also assessed using a trajectory representation that visualizes ...

De Paoli-Iseppi, R., Johansson, P., Menzies, A., Dias, K., Pupo, G., Kakavand, H., Wilmott, J., Mann, G., Hayward, N., Dinger, M., Long, G., Scolyer, R. (2016). Comparison of whole-exome sequencing of matched fresh and formalin fixed paraffin embedded melanoma tumours: implications for clinical decision making. Pathology, 48(3), 261-266. ...

Motivated by recent applications of the Mann–Whitney U test to large data sets we took a critical look at current methods for computing its significance. Surprisingly, we found that the two fastest and most popular tools for exact computation of the test significance, Dinneen and Blakesley’s and Harding’s, can exhibit large numerical errors even in moderately large datasets. In addition, anothe...

The Pre-Whitening (PW), the Trend-Free Pre-Whitening (TFPW) and the Modified Trend-Free PreWhitening (MTFPW) were developed to remove the influence of serial correlations on the MannKendall trend test. The main purpose of this study was to compare the performance of these algorithms for evaluating trends in auto-correlated series. The PW, TFPW and MTFPW were also applied to the monthly values o...

A sensitivity analysis in an observational study determines the magnitude of bias from nonrandom treatment assignment that would need to be present to alter the qualitative conclusions of a naïve analysis that presumes all biases were removed by matching or by other analytic adjustments. The power of a sensitivity analysis and the design sensitivity anticipate the outcome of a sensitivity analy...