condition mean min max ZT0-3 1.157824303 0.6853347120000001 1.630313894 ZT4-7 4.291870945 3.844918819 4.7388230710000006 ZT8-11 5.11534853225 4.8182852865 5.412411777999999 ZT12-15 11.5002153655 8.437968686 14.562462045 ZT16-19 12.1688875725 11.870872819999999 12.466902325 ZT20-23 15.4396121975 15.308114415 15.57110998