condition mean min max ZT0-3 8.322675 8.322675 8.322675 ZT4-7 8.725342000000001 8.725342000000001 8.725342000000001 ZT8-11 7.715585 7.715585 7.715585 ZT12-15 9.5542805 9.5542805 9.5542805 ZT16-19 8.3901585 8.3901585 8.3901585 ZT20-23 7.744202 7.744202 7.744202