condition mean min max ZT0-3 5.62479 5.62479 5.62479 ZT4-7 5.6737 5.6737 5.6737 ZT8-11 16.21535 16.21535 16.21535 ZT12-15 31.47795 31.47795 31.47795 ZT16-19 18.8154 18.8154 18.8154 ZT20-23 8.131375 8.131375 8.131375