condition mean min max ZT0-3 1.6078741666666667 0.8558809999999999 2.6613800000000003 ZT4-7 1.27573 1.27573 1.27573 ZT8-11 0.6575675000000001 0.6575675000000001 0.6575675000000001 ZT12-15 5.1120725 2.058735 8.16541 ZT16-19 6.55927 6.55927 6.55927 ZT20-23 3.4205050000000004 3.4205050000000004 3.4205050000000004