condition mean min max ZT0-3 17.94255 14.50785 21.37725 ZT4-7 21.9277 21.9277 21.9277 ZT8-11 21.95 21.95 21.95 ZT12-15 0 0 0 ZT16-19 19.0901 19.0901 19.0901 ZT20-23 19.18765 19.18765 19.18765