condition mean min max ZT0-3 11.531296666666666 6.61214 16.688299999999998 ZT4-7 8.7346 8.7346 8.7346 ZT8-11 13.1778 13.1778 13.1778 ZT12-15 30.435850000000002 22.3511 38.5206 ZT16-19 16.383200000000002 16.383200000000002 16.383200000000002 ZT20-23 22.940849999999998 22.940849999999998 22.940849999999998