condition mean min max ZT0-3 8.773843 8.773843 8.773843 ZT4-7 8.570861 8.570861 8.570861 ZT8-11 9.415631000000001 9.415631000000001 9.415631000000001 ZT12-15 9.119191 9.119191 9.119191 ZT16-19 9.756030500000001 9.756030500000001 9.756030500000001 ZT20-23 8.3296785 8.3296785 8.3296785