condition mean min max ZT0-3 8.200083333333334 4.25842 11.0408 ZT4-7 4.20508 4.20508 4.20508 ZT8-11 4.681710000000001 4.681710000000001 4.681710000000001 ZT12-15 5.5905925 4.775 6.406185 ZT16-19 8.355785 8.355785 8.355785 ZT20-23 10.770900000000001 10.770900000000001 10.770900000000001