condition mean min max ZT0-3 23.9677 23.9677 23.9677 ZT4-7 15.3665 15.3665 15.3665 ZT8-11 16.64865 16.64865 16.64865 ZT12-15 15.22825 15.22825 15.22825 ZT16-19 20.1872 20.1872 20.1872 ZT20-23 18.46395 18.46395 18.46395