condition mean min max ZT0-3 6.92389 6.92389 6.92389 ZT4-7 7.17619 7.17619 7.17619 ZT8-11 4.27933 4.27933 4.27933 ZT12-15 4.665315 4.665315 4.665315 ZT16-19 5.096535 5.096535 5.096535 ZT20-23 6.1596150000000005 6.1596150000000005 6.1596150000000005