condition mean min max ZT0-3 2.037615 2.018555 2.0566750000000003 ZT4-7 1.7896549999999998 1.7896549999999998 1.7896549999999998 ZT8-11 2.832025 2.832025 2.832025 ZT12-15 0 0 0 ZT16-19 5.05326 5.05326 5.05326 ZT20-23 6.096864999999999 6.096864999999999 6.096864999999999