Spss statistical package for windows v 22

Extracted data were entered into a spreadsheet. Statistical analysis was performed using the IBM SPSS statistical package for Windows v.22 (Armonk, New York, USA). Data were expressed as frequency (percentage) for nominal data, mean ± standard deviation of the mean (SD) for normally distributed continuous variables. Normality was tested using Kolmogorov–Smirnov test. Statistical significance between the study groups regarding the previously mentioned parameters was determined using Chi-square test for categorical variables, and Student’s t-test and ANOVA test for continuous variables. P≤0.05 was considered statistically significant. A simple linear regression test was applied to study the relation between two continuous variables. Multiple logistic regression analyses were performed to study the multiple effects of different variables. The sample size was confirmed retrospectively at the alpha level of 0.05 and the power of analysis at 90% and found to be at least 56 for each group.

Extracted data were entered into a spreadsheet. Statistical analysis was performed using the IBM SPSS statistical package for Windows v.22 (Armonk, New York, USA). Data were expressed as frequency (percentage) for nominal data, mean ± standard deviation of the mean (SD). Statistical significance between the study groups regarding the previously mentioned parameters was determined using chi-square test for categorical variables, and Student’s t-test and ANOVA test for continuous variables. P ≤ 0.05 was considered statistically significant. Simple linear regression test was applied to study the relation between two continuous variables. Multiple logistic regression analyses were performed to study the multiple effects of different variables. The sample size was confirmed retrospectively at alpha level of 0.05 and power of analysis at 90%.