condition mean min max ZT0-3 10.646806666666667 3.58007 14.88825 ZT4-7 1.9011 1.9011 1.9011 ZT8-11 4.80181 4.80181 4.80181 ZT12-15 5.7305825 3.93971 7.521455 ZT16-19 11.2315 11.2315 11.2315 ZT20-23 17.031 17.031 17.031