condition mean min max ZT0-3 6.162645 6.133425000000001 6.191865 ZT4-7 5.79775 5.79775 5.79775 ZT8-11 5.88272 5.88272 5.88272 ZT12-15 0 0 0 ZT16-19 6.841315 6.841315 6.841315 ZT20-23 8.16545 8.16545 8.16545