condition mean min max ZT0-3 6.5385075 6.29523 6.781785 ZT4-7 6.03897 6.03897 6.03897 ZT8-11 7.537145 7.537145 7.537145 ZT12-15 0 0 0 ZT16-19 8.069015 8.069015 8.069015 ZT20-23 8.580375 8.580375 8.580375