condition mean min max ZT0-3 2.427685 1.88736 3.31441 ZT4-7 1.2338300000000002 1.2338300000000002 1.2338300000000002 ZT8-11 2.033335 2.033335 2.033335 ZT12-15 3.25011 3.110855 3.3893649999999997 ZT16-19 3.86371 3.86371 3.86371 ZT20-23 4.1396299999999995 4.1396299999999995 4.1396299999999995