condition mean min max ZT0-3 3.902875 2.71252 5.09323 ZT4-7 2.70501 2.70501 2.70501 ZT8-11 6.42887 6.42887 6.42887 ZT12-15 0 0 0 ZT16-19 4.88522 4.88522 4.88522 ZT20-23 3.53457 3.53457 3.53457