| calc_chunks | Calculate data chunk indices |
| calc_duration | Calculate durations of time |
| chunk_data_ | Break data into chunks |
| paste | Concatenate strings |
| paste0 | Concatenate strings |
| paste_efs | Paste event-free survival |
| paste_freq | Paste frequency |
| paste_mean | Paste mean |
| paste_median | Paste median |
| test_hypothesis | Test the null hypothesis |