condition mean min max ZT0-3 7.993895 7.599315 8.388475 ZT4-7 9.298095 9.298095 9.298095 ZT8-11 8.879705000000001 8.879705000000001 8.879705000000001 ZT12-15 0 0 0 ZT16-19 13.1629 13.1629 13.1629 ZT20-23 8.84508 8.84508 8.84508