Which ONE of the following statements about the SES Plan used in the sample size formula for

Which ONE of the following statements about the SES ΔPlan used in the sample size formula for continuous data is INCORRECT?

A. ΔPlan is calculated as the difference in means divided by the standard deviation of the outcome.

B. Goes down with a larger standard deviation C. Goes up with a larger standard deviation.

D. Goes up with a larger mean difference.

E. A ΔPlan of 0.5 is equivalent to a difference of half a standard deviation between the group means.

Suppose we are planning a new RCT in patients with venous leg ulcers to see if a new treatment with a special chemically impregnated dressing called ‘Quickheal’ will lead to improved outcomes compared to a standard dressing (control). The primary outcome for the trial will be the number of weeks the patients are ulcer free over the 12‐month post‐randomisation follow‐up period. We know from published data that the mean number of ulcer‐free weeks is 20 (with a standard deviation of 20 weeks). Suppose the effect of the new dressing on ulcer healing will be considered important if it increases the number of ulcer‐free weeks, at one‐year post‐randomisation, by at least eight weeks.