condition mean min max ZT0-3 11.2756625 10.996425 11.5549 ZT4-7 8.20238 8.20238 8.20238 ZT8-11 6.992535 6.992535 6.992535 ZT12-15 0 0 0 ZT16-19 9.052859999999999 9.052859999999999 9.052859999999999 ZT20-23 10.637725 10.637725 10.637725