condition mean min max ZT0-3 8.686153 8.686153 8.686153 ZT4-7 8.823357999999999 8.823357999999999 8.823357999999999 ZT8-11 8.815425 8.815425 8.815425 ZT12-15 8.5153375 8.5153375 8.5153375 ZT16-19 8.6112145 8.6112145 8.6112145 ZT20-23 9.6033165 9.6033165 9.6033165