condition mean min max ZT0-3 29.389345 29.389345 29.389345 ZT4-7 23.255823499999998 23.255823499999998 23.255823499999998 ZT8-11 21.9127065 21.9127065 21.9127065 ZT12-15 25.631514000000003 25.631514000000003 25.631514000000003 ZT16-19 32.9630455 32.9630455 32.9630455 ZT20-23 27.889224 27.889224 27.889224