Also based on the data observations and alpha level of 0.05, there is at least a 90 % chance of detecting a difference of standard deviation of 0.0023297 and at most a 60%% chance of detecting a difference of standard deviation of 0.0013632.
To detect 0.2 effect size (one-fifth difference of standard deviation) for quality of palliative care (the Care Evaluation Scale) under statistical power of 0.8, 558 responses for each pre-intervention and post-intervention period is required for the analyses.
The mean scores for these patients with AS are considerably lower than mean scores of the general US population [ 29], with differences of 1.7 standard deviation units for the PCS and 0.7 standard deviation units for the MCS.
For the composite primary outcome, post hoc power calculations from the observed standard errors of differences indicate 80% power was available to detect mean marginal differences of 0.49 standard deviations.
Skewness values show differences of several standard deviations when comparing the deterministic, -PE and -CE models with the reference model, and this may be a general phenomena that is useful in model fitting and model selection.
We defined adjusted differences of ≥0.2 standard deviations [SD]) to be quantitatively meaningful.
The right panel of Fig. 4 shows the distribution of the differences of the standard deviations in the two subsets.
