condition mean min max ZT0-3 22.472447 22.472447 22.472447 ZT4-7 19.2651675 19.2651675 19.2651675 ZT8-11 21.4344635 21.4344635 21.4344635 ZT12-15 21.4637515 21.4637515 21.4637515 ZT16-19 27.4139515 27.4139515 27.4139515 ZT20-23 27.8281275 27.8281275 27.8281275