condition mean min max ZT0-3 8.622268333333334 4.148085 16.46685 ZT4-7 9.153780000000001 9.153780000000001 9.153780000000001 ZT8-11 8.314155 8.314155 8.314155 ZT12-15 11.6756575 8.682565 14.66875 ZT16-19 8.480834999999999 8.480834999999999 8.480834999999999 ZT20-23 9.302775 9.302775 9.302775