Statistical Analysis
The StudentYFisher t test with a number of degrees of freedom
of (n-1) was used formatched data pairs of continuous variables
that followed a normal distribution. For continuous variables
that did not followa normal distribution, either the nonparametric
paired-differenceWilcoxon signed-rank test or theMannYWhitney
U test was used depending on the type of data. The chi-squared
test was used to analyze categorical variables. Statistical analyses
were carried out using SPSS version 15.0 (SPSS, Inc., Chicago,
IL, USA). The level of significance chosen was 5%.