condition mean min max ZT0-3 3.279675 3.279675 3.279675 ZT4-7 1.629405 1.629405 1.629405 ZT8-11 5.64656 5.64656 5.64656 ZT12-15 4.057965 4.057965 4.057965 ZT16-19 4.96559 4.96559 4.96559 ZT20-23 3.66299 3.66299 3.66299