condition mean min max ZT0-3 13.2013229575 11.3519261 15.050719815 ZT4-7 9.49019989 8.6221793955 10.358220384500001 ZT8-11 11.1501110745 9.2949040615 13.005318087500001 ZT12-15 17.215327455 14.211804794999999 20.218850115 ZT16-19 23.975019717499997 22.289240364999998 25.66079907 ZT20-23 24.646475285 23.266758835 26.026191734999998