condition mean min max ZT0-3 17.641745 9.912585 22.4983 ZT4-7 9.554615 9.554615 9.554615 ZT8-11 9.03104 9.03104 9.03104 ZT12-15 10.320015 9.70788 10.93215 ZT16-19 11.6204 11.6204 11.6204 ZT20-23 21.224 21.224 21.224