condition mean min max ZT0-3 16.67869586 14.90829851 18.44909321 ZT4-7 11.5813991005 11.258529831 11.90426837 ZT8-11 9.28307923225 9.182281294 9.3838771705 ZT12-15 9.7661241735 9.2216000005 10.310648346499999 ZT16-19 13.407724481750002 13.0888150885 13.726633875000001 ZT20-23 15.2377421825 15.177316954999998 15.29816741