condition mean min max ZT0-3 6.32407 2.3073300000000003 9.315304999999999 ZT4-7 1.718725 1.718725 1.718725 ZT8-11 2.6008250000000004 2.6008250000000004 2.6008250000000004 ZT12-15 7.024945 6.171735 7.878155 ZT16-19 7.86505 7.86505 7.86505 ZT20-23 10.19624 10.19624 10.19624