condition mean min max ZT0-3 5.762595 5.762595 5.762595 ZT4-7 3.4959 3.4959 3.4959 ZT8-11 3.7750500000000002 3.7750500000000002 3.7750500000000002 ZT12-15 3.6173900000000003 3.6173900000000003 3.6173900000000003 ZT16-19 8.931905 8.931905 8.931905 ZT20-23 7.01343 7.01343 7.01343