condition mean min max ZT0-3 9.434351666666666 6.132045 11.68173 ZT4-7 5.938725 5.938725 5.938725 ZT8-11 5.849600000000001 5.849600000000001 5.849600000000001 ZT12-15 10.17117 9.56619 10.776150000000001 ZT16-19 10.737335 10.737335 10.737335 ZT20-23 13.879 13.879 13.879