*3.2.4 Data analysis*

Pairwise comparisons confirmed that tactical regional and federal-level subsamples did not significantly differ from each other across all time points for cortisol and self-reported stress data, and sufficient to combine regional and federal subsamples into a single tactical sample group.

For subjective stress comparisons, self-reported stress responses on the PSQ had a non-normal distribution violating the assumptions of a t-test. Therefore, a Wilcoxon rank sum test was used to compare overall reported stress between frontline and tactical officers.

Average diurnal cortisol levels were calculated for each police participant at each time point. Factorial ANOVA was performed to compare specific diurnal time point cortisol levels across each group. Repeated-measures mixed-model analysis of variance (ANOVA) with Bonferroni corrections was used to compare multiple pairwise differences in cortisol levels between groups across time points.
