4.8. Statistical Analysis
All IPA data were analyzed by Fischer’s exact test within the IPA core analysis program. Power calculations were performed according to earlier studies on Ki-67 protein from FNA biopsies since mRNA studies on normal breast tissue were never previously performed when the study was designed.Non-IPA data are presented as the arithmetic mean, median, and 25th–75th percentile. Comparisons within the same group of women were carried out by Wilcoxon’s signed-rank test for paired observations and between the two groups by Mann–Whitney U-test. Correlations were performed by Spearman’s rank correlation test. Non-parametric methods were chosen due to the skewed distribution of data. The significance level was set at 