Two-tailed P-values < 0.05 were considered to be statistically significant, and all statistical analyses were conducted using Stata software version 12.1 (Stata Corporation, College Station, TX, USA).
All statistical analyses were conducted with R v.2.8.1, and p-values were considered statistically significant at α < 0.05.
All statistical analyses were conducted with R v.2.10.1 and STATISTICA v.6.0, and P values were considered statistically significant at α<0.05.
All statistical analyses were conducted using Stata Statistical Software (Release 12.1, 2011, Stata Corporation, College Station, TX); p <0.05 was considered statistically significant.
Statistical analyses were conducted using SAS version 9.1 (SAS Institute, Cary, NC), and P values <0.05 were considered statistically significant.
All statistical analyses were conducted by using SPSS 13.0 (SPSS Inc., Chicago, IL), and P < 0.05 was considered statistically significant.
Statistical analyses were conducted using SPSS, version 19 (IBM Software, Hampshire, U.K ., and P < 0.05 was considered statistically significant.
Statistical analyses were conducted using the SAS software (ver.9.1, Cary, NC), and P < 0.05 was considered to be statistically significant.
Statistical analyses were conducted using SAS, version 9.4, (SAS Institute, Inc., Cary, North Carolina), and a P value < 0.05 was considered statistically significant.
Statistical analyses were conducted with two models.
