condition mean min max ZT0-3 2018.6 2018.6 2018.6 ZT4-7 1752.4 1752.4 1752.4 ZT8-11 1920.4 1920.4 1920.4 ZT12-15 2021.6999999999998 2021.6999999999998 2021.6999999999998 ZT16-19 2487.8500000000004 2487.8500000000004 2487.8500000000004 ZT20-23 2216.05 2216.05 2216.05