// schedule - like a missing task list, for example. If such a
// schedule is present, we can't generate any interval for it.
if (taskList.getSchedule().getEffectiveDate() == null)
return null;
ConfidenceInterval result = super.getConfidenceInterval(taskList);
// always recenter the time error interval - wide intervals are
// of little consequence for rollups. Bias causes bigger
// problems.
if (isCentered(result) == false)