condition mean min max ZT0-3 8.62764 8.62764 8.62764 ZT4-7 8.5111865 8.5111865 8.5111865 ZT8-11 7.910299 7.910299 7.910299 ZT12-15 8.8365045 8.8365045 8.8365045 ZT16-19 8.5747635 8.5747635 8.5747635 ZT20-23 8.3694575 8.3694575 8.3694575