condition mean min max ZT0-3 3.3704599999999996 3.3704599999999996 3.3704599999999996 ZT4-7 1.9074849999999999 1.9074849999999999 1.9074849999999999 ZT8-11 2.010745 2.010745 2.010745 ZT12-15 2.12336 2.12336 2.12336 ZT16-19 3.1471850000000003 3.1471850000000003 3.1471850000000003 ZT20-23 2.524165 2.524165 2.524165