the sample size
was calculated using the formula of Estimation
of Mean sample size for comparative studies
in accordance with a pilot study with a sample
size of 20 patients in each group; the mean and
standard deviation were respectively 18.9±5.6,
20.9±6.1, 1 7.8±4.9, d = 3 .1, S 1=6.1, S 2=4.9,
β=0.2. The sample size was calculated as 50 in
each group