condition mean min max ZT0-3 6.04863 6.04863 6.04863 ZT4-7 4.400565 4.400565 4.400565 ZT8-11 2.5828949999999997 2.5828949999999997 2.5828949999999997 ZT12-15 4.13527 4.13527 4.13527 ZT16-19 6.17943 6.17943 6.17943 ZT20-23 6.568054999999999 6.568054999999999 6.568054999999999