condition mean min max ZT0-3 8.480291666666666 7.771405 9.53238 ZT4-7 8.1488 8.1488 8.1488 ZT8-11 8.180395 8.180395 8.180395 ZT12-15 6.7411449999999995 5.942635 7.539655 ZT16-19 7.3435950000000005 7.3435950000000005 7.3435950000000005 ZT20-23 9.355129999999999 9.355129999999999 9.355129999999999