True. In our case it is wound size area reduction.
I calculated using the software :
http://www.statskingdom.com/sample_size_all.html
As per data from available literature, considering the mean of wound size area is reduced to 13.18 +/- 19.64 cm2 with use of standard dressing and estimated mean of wound size area will be reduced to 5.40 cm2 with use of new dressing, keeping alpha value as 0.05 with 80% power, the minimum number of patients required are 50 patients.
I wanted to confirm if this is the correct way to calculate sample size.
Reference study: file attached.