condition mean min max ZT0-3 20.439063 20.439063 20.439063 ZT4-7 23.227345 23.227345 23.227345 ZT8-11 27.9050365 27.9050365 27.9050365 ZT12-15 22.6007855 22.6007855 22.6007855 ZT16-19 22.8249345 22.8249345 22.8249345 ZT20-23 21.4059915 21.4059915 21.4059915