Table 1

Descriptions of statistical tests

Data structureType of testResultEffect sizePower
aNon-normal
US condition:
W(11) = 0.7185, p = 0.0018
ED condition:
W(11) = 0.6417, p = 4.38e-04
Wilcoxon rank-sum testZ = 2.6275, p = 0.0086d = 1.30180.8438
bNon-normal
US condition:
W(9) = 0.7890, p = 0.0141
ED condition:
W(9) = 0.5623, p = 2.6799e-04
Wilcoxon rank-sum testZ = 0.1890, p = 0.8501d = 0.01350.0501
cNormal
US condition:
W(9) = 0.9659 , p = 0.8508
ED condition:
W(9) = 0.9713 p = 0.9027
Welch’s t testt(17.3329) = 0.2777,
p = 0.7845
d = 0.03430.0506
dNon-normal
US condition:
W(7) = 0.8499, p =0.0951
Control condition:
W(7) = 0.9543 p = 0.7547
Wilcoxon rank-sum testZ =100, p = 1.554E-4d = 3.6130.99
eNon-normal
US condition:
W(7) = 0.8802, p = 0.189
Control condition:
W(7) = 0.8802, p = 0.0274
Wilcoxon rank-sum testp = 0.1605d = 1.34320.68
  • Letters (leftmost column) correspond to p values of statistical tests as reported in Results. The data structure, test type, result, effect size, and statistical power of these tests are described. Results of Shapiro–Wilk test for normality of data in US and electrode displacement (ED) conditions (α = 0.05) are reported under Data structure. Normally distributed data were compared with Welch’s t test, and non-normal data were compared with the nonparametric Wilcoxon rank-sum test. Effect sizes were calculated as Cohen’s d with correction for small sample sizes as described by Durlak (2009).