condition mean min max ZT0-3 17.40555 17.40555 17.40555 ZT4-7 11.21445 11.21445 11.21445 ZT8-11 8.09029 8.09029 8.09029 ZT12-15 11.22005 11.22005 11.22005 ZT16-19 17.68635 17.68635 17.68635 ZT20-23 18.884149999999998 18.884149999999998 18.884149999999998