The study was designed to have 80% power to detect a treatment response of 20%
(that is, above the response to placebo),
with a standard deviation
(derived from existing data)
of 35%,at a significance level of 0.05.
We estimated that 120 participants would be needed.
We anticipated that around 20% of participants would be withdrawn
and therefore aimed to recruit 152 participants,
comprising 76 adults and 76 children.