4.4. Statistics

Quantitative variables were calculated in mean values and standard deviations (SD). Qualitative variables were expressed in absolute (N) and relative (%) frequencies. Pearson’s x2 test or Fisher’s exact test were used to comparing ratios where necessary. The student’s t-test was used to compare quantitative variables between two groups.

A stepwise multiple logistic regression analysis (p for removal was set at 0.1 and p for entry was set at 0.05) was conducted in order to investigate independently associated factors with the existence of positive GBS. Adjusted odds ratios with 95% confidence intervals were computed from the results of the logistic regression analysis. All p-values reported are two-tailed.

Statistical significance was set at 0.05. Statistical analysis was conducted using SPSS statistical software (version 23.0).