2.3. Statistical analysis
Stepwise multiple linear regression was performed to identify the best
predictor among various parameters of the IOS by using height, age, body
weight, and gender as potential independent variables. The
5th percentile and 95th percentile
was calculated using parametric methods. All statistical analyses were
performed using IBM SPSS Statistics version 20 (IBM, Armonk, NY, USA).P <0.05 was considered statistically significant.