condition mean min max ZT0-3 8.757703333333334 2.2202599999999997 12.30815 ZT4-7 2.274355 2.274355 2.274355 ZT8-11 7.49325 7.49325 7.49325 ZT12-15 10.07518 9.46351 10.68685 ZT16-19 11.6974 11.6974 11.6974 ZT20-23 15.28355 15.28355 15.28355