x = [10 12 15 8 11];
y = [14 18 16 12 13];
d = mean(x-y)/std(x-y)
eff = meanEffectSize(x, y, "Paired", true, "Effect", "cohen")
And yes, you are correct, the difference is because of hedgesCorrection. Also apparently, the function considers within subject correlation. Let's check it in R with effsize::cohen.d
%# in R
% x = c(10 ,12, 15, 8, 11);
% y = c(14 ,18 ,16,12,13);
% effsize::cohen.d(x, y, paired = T, within = F, hedges.correction = F)
Cohen's d
d estimate: -1.744163 (large)
95 percent confidence interval:
lower upper
-3.3816056 -0.1067208
% effsize::cohen.d(x, y, paired = T, within = T, hedges.correction = T)
Hedges's g
g estimate: -1.084754 (large)
95 percent confidence interval:
lower upper
-1.8930902 -0.2764184
