condition mean min max ZT0-3 15.959483333333333 11.690650000000002 18.59095 ZT4-7 19.43555 19.43555 19.43555 ZT8-11 17.8977 17.8977 17.8977 ZT12-15 20.8905 19.55845 22.22255 ZT16-19 22.07105 22.07105 22.07105 ZT20-23 24.33645 24.33645 24.33645