Statistical analysis
SPSS 15.0 for Windows was used for statistical analysis. Descriptive
statistics were given as numbers and percentages for categorical
variables, and as median and interquartile range for numeric variables.
The rates in independent groups were compared using the Chi-Square Test.
When the numerical variable did not meet the normal distribution
condition, comparisons of two independent groups were made using the
Mann Whitney U Test. Relationships between numerical variables were
analyzed using Spearman Correlation Analysis. Statistical significance
level of alpha was accepted as p <0.05.