condition mean min max ZT0-3 9.2311575 6.49127 11.971045 ZT4-7 9.510819999999999 9.510819999999999 9.510819999999999 ZT8-11 19.60575 19.60575 19.60575 ZT12-15 0 0 0 ZT16-19 22.350250000000003 22.350250000000003 22.350250000000003 ZT20-23 16.387999999999998 16.387999999999998 16.387999999999998