condition mean min max ZT0-3 10.510885 10.510885 10.510885 ZT4-7 9.324611 9.324611 9.324611 ZT8-11 9.352539 9.352539 9.352539 ZT12-15 8.773422 8.773422 8.773422 ZT16-19 8.17241 8.17241 8.17241 ZT20-23 9.0038595 9.0038595 9.0038595