condition mean min max ZT0-3 5.399626666666666 3.802 7.34567 ZT4-7 3.5973300000000004 3.5973300000000004 3.5973300000000004 ZT8-11 4.2458100000000005 4.2458100000000005 4.2458100000000005 ZT12-15 4.8057175 3.2541399999999996 6.357295000000001 ZT16-19 5.53864 5.53864 5.53864 ZT20-23 6.611364999999999 6.611364999999999 6.611364999999999