condition mean min max ZT0-3 5.149775 4.322229999999999 5.97732 ZT4-7 7.59901 7.59901 7.59901 ZT8-11 8.364085 8.364085 8.364085 ZT12-15 0 0 0 ZT16-19 10.354585 10.354585 10.354585 ZT20-23 8.984365 8.984365 8.984365