a nonsignificant trendp = .09
Given that in 40% of the sample the Optimal versus Non-Optimal difference was quite small, it is not surprising that the observed difference between the Optimal and Non-Optimal means in the full sample was relatively small; they differed at the level of a nonsignificant trend (mean difference = 1.78; pooled SD = 6.38; t = 1.73, 152, p = .09; d = .28, 95% confidence interval −.04 to .60).