condition mean min max ZT0-3 8.2233 8.2233 8.2233 ZT4-7 6.750055 6.750055 6.750055 ZT8-11 6.299645 6.299645 6.299645 ZT12-15 6.433335 6.433335 6.433335 ZT16-19 8.155775 8.155775 8.155775 ZT20-23 6.279235 6.279235 6.279235