condition mean min max ZT0-3 22.016925 21.7223 22.31155 ZT4-7 17.51135 17.51135 17.51135 ZT8-11 14.8742 14.8742 14.8742 ZT12-15 0 0 0 ZT16-19 20.2065 20.2065 20.2065 ZT20-23 21.6348 21.6348 21.6348