2.9. Statistical Analysis
pain
REGRESSION
Normal distribution of pain data was evaluated by the Kolmogorov–Smirnov test. The results showed that distribution of pain data was normal at 2, 4, 8, and 12 hours. Thus, comparisons at these time points were performed by the Considering the differences in distribution of data at different time points, the quantitative trend of pain over time was analyzed by generalized estimating equation (GEE). Since the trend of pain reduction over time was not linear, the Spline technique was used to analyze the trend of pain score change over time such that one line was considered from 2 to 10 hours and a second line was considered from 10 to 48 hours post-treatment. The overall form of the linear regression formula was as follows:Mean pain score:Finally, Fisher's exact test was used to compare the two groups regarding complete analgesia (NRS score 0) at different time points. All statistical analyses were carried out using SPSS version 20 at the 0.05 level of significance.