condition mean min max ZT0-3 7.369365 6.95546 7.78327 ZT4-7 8.403514999999999 8.403514999999999 8.403514999999999 ZT8-11 6.04711 6.04711 6.04711 ZT12-15 0 0 0 ZT16-19 6.8334600000000005 6.8334600000000005 6.8334600000000005 ZT20-23 6.88874 6.88874 6.88874