condition mean min max ZT0-3 19.498195 19.498195 19.498195 ZT4-7 20.4581205 20.4581205 20.4581205 ZT8-11 22.5793085 22.5793085 22.5793085 ZT12-15 24.781454 24.781454 24.781454 ZT16-19 31.69143 31.69143 31.69143 ZT20-23 25.171376000000002 25.171376000000002 25.171376000000002