Wilcoxon two-sample test

Wilcoxon two-sample test

[′wil‚käk·sən ¦tü ¦sam·pəl ‚test]
(statistics)
The test based upon the rank sum of treated (or untreated) subjects.
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For the S/V treatment, this is consistent with the fact that males indicated significantly less risk aversion than did women in their responses to the financial risk survey statement (means test p-value <.10; Wilcoxon two-sample test p-value <.09).
(30) In the V/S treatment, men are significantly more accurate than women when predicting for male targets (both means test and Wilcoxon two-sample test p-values [less than or equal to] .01 for both P1 and P2).
Table 1: Results for the significance of the average body weight t Test: Paired Two Sample for Means El greutate EF greutate Mean 53 583 53.75 Variance 72 629 30.75 Observations 12000 12 Pearson Correlation 0.886 Hypothesized Mean Difference 0 df 11 000 t Stat 0.130 P(T<=t) onetai 0.449 t Critical onerai 1.796 P(T-t=l)lwo tai 0.899 t Critical two-tai 2.201 Wilcoxon Two-Sample Test Statistic 151.5 Normal Approximation Z 0.0583 One-Sided Pr > Z 0.4768 Two-Sided Pr > |Z| 0.9535 t Approximation One-Sided Pr > Z 0.477 Two-Sided Pr > |Z| 0.954 Z includes a continuity correction of 0.5.
We used a Wilcoxon two-sample test to compare the mean number of woodpecker attacks on white ash and green ash.
The mean time woodpeckers on ash trees engaged in foraging behaviors was 187.0 [+ or -] 161.9 s (n = 9) while the mean time on non-ash trees (n = 17) was significantly less (38.2 [+ or -] 42.5 s, Wilcoxon two-sample test, C = 128.5, P < 0.005).
To assess differences in bottled water samples obtained from imported and in-house brands, the log concentration of endotoxin and bacteriological cell count at baseline was compared using the Wilcoxon two-sample test. Simple linear regression analysis was performed to test the effect of the average log concentration of endotoxin on the average log bacteriological cell count between bottled water samples (between effect model) :
I calculated the CVs for each clone, then averaged these clonal CVs for each clonal group (breeding mode) for each experiment, and finally used a Wilcoxon two-sample test (Sokal and Rohlf 1981) to determine whether significant differences in sensitivity (based on CVs) exist between asexuals and sexuals.
Coefficients of variation (CVs) of [LT.sub.50]s were calculated for each clonal group across acclimation temperature treatments for each of the three experiments, and a Wilcoxon two-sample test was performed as described previously.
- The first approach was based on the conventional Wilcoxon two-sample test (also known as the Mann-Whitney U test) as proposed by Simberloff and Martin (1991).
In the study reported here, observed patterns of island occupancy were tested against two types of null models; a random one (the conventional Wilcoxon two-sample test as was used in several previous studies, e.g., Schoener and Schoener 1983, Simberloff and Levin 1985, Simberloff and Martin 1991), and an ordered one.
The quality of CPR measures was plotted using box-and-whisker plots and compared between the control and the intervention groups using t-tests or Wilcoxon two-sample tests where appropriate.
The t and the Wilcoxon two-sample tests are actually testing different things: E(X) = E(Y) for the t, but P(X [is greater than] Y) = 0.5 for the Wilcoxon.