Friedman test

Results of the Friedman test, where jt> s 0.10 jt> s 0.05. The values used in the Friedman test are means of the field and laboratory replicates. metal concentrations follow the gradient site 1 > site 2 > site 3. " metal concentrations either follow the gradient site 3 > site 2 > site 1, or do not show an apparent gradient. 

The data from the analyses conducted on the liquid phase are summarized in Table 6. The results of the Friedman test, performed to evaluate the influence of soil contamination level on Cu + activities, are presented in Table 4. In all soil components, the Cu + activities are significantly influenced by the level of soil contamination, with the absolute Cu + activities decreasing with distance from the smelter (Table 6 and Fig. 4a). As shown in Table 6 and Fig. 4a, a significant soil component difference (p 0.10) is found only at site 3, where the bulk soil hosts relatively higher mean free Cu + activities, while the lowest amounts are measured in the outer rhizosphere. Thus, unlike the results presented for Cu in the solid phase, the inner rhizosphere is not the soil component where the highest Cu + activities are found. In fact, no general trend emerges for free Cu + activities between the three soil components (Fig. 4a). 

Flank Marking. LOT transections virtually eliminated flank marking LOT-Cut females marked significantly less than sham females (collapsed across odors and estrous day U = 1230.5, p <. 00001 Figure 4). This dramatic decrease in flank marking was apparent across all odor conditions and estrous cycle days (Figure 4). Indeed, sham females flank marked at different rates in different odor conditions (collapsed across estrous days Friedman Test Statistic = 9.875, p <. 005) but LOT-Cut females did not. 

Exploitation of the data via Based on the ranks, a Friedman test is set up for each... 

The Friedman test could alternatively be used in the reverse form assuming that the three analytical methods give indistinguishable results, the same procedure could be used to test differences between the four plant extracts. In this case k and n are 4 and 3 respectively, and the reader may care to verify that R is 270 and that the resulting x value is 9.0. This is higher than the critical value for P= 0.05, n = 3, k=A, which is 7.4. So in this second application of the test we can reject the null hypothesis, and state that the four samples do differ in their pesticide levels. Further tests, which would allow selected comparisons between pairs of samples, are then available. 

Friedman test), or a species of toad, Xenopus toBvis (Hogben test), and the observation of subsequent histological changes. 

The Friedman test only requires twenty-four to forty-eight hours, and for this reason is sometimes preferable. The relative merits of the three tests are discussed by Crew (1939). 

Fig. 2-4. Mean pulse height versus quantum energy, to illustrate pulse-height selection of characteristic lines. Side window tube, 3-in. diameter 0.005-in. wire operating at 1275 v filled with argon plus 10% ethylene total pressure, 15 cm of mercury (proportional counter) gain, 3.5 X 104. (After Friedman, Birks, and Brooks, A STM Spec. Tech. Publ., No. 157, page 3. Copyright 1954. American Society for Testing Materials.)...

Young, D.S. Thomas, D.W. Friedman, R.B..and Pestaner, L.C. "Effects of Drugs on Clinical Laboratory Tests". Clin. 

Young, D.S. Friedman, R.B. and Pestaner, L.C. "Automatic Monitoring of Drug-Laboratory Test Interactions" Drug Interactions, pp. 393-401, Morselll, P.L., Garattlnl, S., and Cohen, S.N., Editors, Raven Press, New York, 1974. 

The results of such multiple paired comparison tests are usually analyzed with Friedman s rank sum test [4] or with more sophisticated methods, e.g. the one using the Bradley-Terry model [5]. A good introduction to the theory and applications of paired comparison tests is David [6]. Since Friedman s rank sum test is based on less restrictive, ordering assumptions it is a robust alternative to two-way analysis of variance which rests upon the normality assumption. For each panellist (and presentation) the three products are scored, i.e. a product gets a score 1,2 or 3, when it is preferred twice, once or not at all, respectively. The rank scores are summed for each product i. One then tests the hypothesis that this result could be obtained under the null hypothesis that there is no difference between the three products and that the ranks were assigned randomly. Friedman s test statistic for this reads... 

Friedman et al. (2000) tested this approach on a data set for yeast cell cycle expression patterns provided by Spellman and co-workers (1998), writing that This data set contains 76 gene expression measurements of the mRNA levels of 6177 S. cerevisiae ORFs. These experiments measure six... 

Dowd RW. 1990. Review of studies concerning effects of well casing materials on trace measurements of organic compounds. In Friedman D, ed. Waste Testing and Quality Assurance Second Volume. 31-42. 

Fig. 17.3 Proportion of spotted hyena pastings that were overmarks by age and sex. Males increased their overmarking activity with age (Wilcoxon signed-rank test, S = 32.5, P = 0.04), however, females did not (cub vs. subadult S = — 15.5, P = 0.24 across subadult periods N = 6, Friedman ANOVA x2 = 3.5, P = 0.17). Although male and female cubs did not differ in their frequency of overmarking (Mann-Whitney U test, U = 75, P = 0.67), a sex difference was apparent among subadults (U = 37, P = 0.02)...

Separate analyses were performed for the test series conducted at 34 and 36 weeks PCA. For each behavioural measure the results were compared across the 4 odour stimuli with Friedman s tests. A similar series of within-subject comparisons was performed for the changes in baseline cardiac rates following odour presentations. 

Wang YY, Marsden PJ, Flessel CP, et al. 1990. Evaluation and validation of protocols for measurement of the mutagenicity of environmental samples. In Friedman D, ed. Waste testing and quality assurance ... 

Ordinal or numerical Mann-Whitney U test Wilcoxon signed rank test Kruskal-Wallis Friedman... 

Assurance Third Volume, ASTM STP 1075, D. Friedman, Ed., American Society for Testing and Materials, Philadelphia. 154-169. 

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