condition mean min max ZT0-3 6.170535 6.170535 6.170535 ZT4-7 4.335965 4.335965 4.335965 ZT8-11 4.54659 4.54659 4.54659 ZT12-15 5.128655 5.128655 5.128655 ZT16-19 6.19464 6.19464 6.19464 ZT20-23 5.894415 5.894415 5.894415