condition mean min max ZT0-3 12.942533333333333 10.3358 15.8098 ZT4-7 9.262285 9.262285 9.262285 ZT8-11 9.63827 9.63827 9.63827 ZT12-15 17.71715 15.732500000000002 19.7018 ZT16-19 18.779049999999998 18.779049999999998 18.779049999999998 ZT20-23 18.6319 18.6319 18.6319