condition mean min max ZT0-3 6.696245 6.023075 7.963615000000001 ZT4-7 5.344005 5.344005 5.344005 ZT8-11 3.76752 3.76752 3.76752 ZT12-15 5.6153275 5.50296 5.727695000000001 ZT16-19 4.679955 4.679955 4.679955 ZT20-23 5.83667 5.83667 5.83667