condition mean min max ZT0-3 5.894435 5.894435 5.894435 ZT4-7 5.95699 5.95699 5.95699 ZT8-11 8.722075 8.722075 8.722075 ZT12-15 17.4681 17.4681 17.4681 ZT16-19 11.27131 11.27131 11.27131 ZT20-23 6.439285 6.439285 6.439285