condition mean min max ZT0-3 19.837675 18.6687 21.00665 ZT4-7 11.6359 11.6359 11.6359 ZT8-11 11.6951 11.6951 11.6951 ZT12-15 0 0 0 ZT16-19 14.9147 14.9147 14.9147 ZT20-23 17.5899 17.5899 17.5899