condition mean min max ZT0-3 17.619135 17.619135 17.619135 ZT4-7 12.1360425 12.1360425 12.1360425 ZT8-11 13.508532500000001 13.508532500000001 13.508532500000001 ZT12-15 13.6428215 13.6428215 13.6428215 ZT16-19 16.7580645 16.7580645 16.7580645 ZT20-23 13.0921765 13.0921765 13.0921765