The required sample size for this s

The required sample size for this study was estimated using
a power analysis suggested by Erdfelder et al. (1996).
Considering a medium effect size (f 2 = 0Æ15), a of 0Æ05,
95% power (1 b), and a total of ten independent variables,
a sample size of at least 172 patients was required to obtain
the G*power (Faul et al. 2007).