condition mean min max ZT0-3 12.8 12.8 12.8 ZT4-7 15.0 15.0 15.0 ZT8-11 13.649999999999999 13.649999999999999 13.649999999999999 ZT12-15 7.8 7.8 7.8 ZT16-19 15.3 15.3 15.3 ZT20-23 20.6 20.6 20.6