The SPSS 15.0 for Windows software package (SPSS, Chicago, IL, USA) was used for statistical analyses of the data. Shapiro-Wilk test was preferred to determine the normality of statistical distribution for continuous variables. One-way analysis of variance (ANOVA) or the Kruskal-Wallis test was used for continuous variables. Categorical data were examined using Fisher’s exact test and presented as the number of cases and percentages. Continuous variables were demonstrated as the mean±standard deviation (SD) or median and interquartile ranges. Bonferroni correction was used to control for type I errors for all possible multiple comparisons. Spearman’s correlation test was performed to determine correlations between kisspeptin and other study parameters. A value of p<0.05 was accepted as statistically significance.
The DSS statistical software package for research sample size calculations was used for sample size calculation21 . Our primary aim of the current study was to analyze the differences in kisspeptin levels among the groups. A minimum of 30 participants in each group would be required to reveal a difference of at least 10% between the groups, with a power of 80% at the 5% significance level. This difference of 10% was determined both based on a pilot study and our clinical experiments.
The DSS statistical software package for research sample size calculations was used for sample size calculation21 . Our primary aim of the current study was to analyze the differences in kisspeptin levels among the groups. A minimum of 30 participants in each group would be required to reveal a difference of at least 10% between the groups, with a power of 80% at the 5% significance level. This difference of 10% was determined both based on a pilot study and our clinical experiments.