condition mean min max ZT0-3 17.58355 16.9771 18.189999999999998 ZT4-7 24.72065 24.72065 24.72065 ZT8-11 25.3016 25.3016 25.3016 ZT12-15 0 0 0 ZT16-19 29.40755 29.40755 29.40755 ZT20-23 21.5325 21.5325 21.5325