condition mean min max ZT0-3 3.0169925 2.9978350000000002 3.03615 ZT4-7 3.45306 3.45306 3.45306 ZT8-11 4.64526 4.64526 4.64526 ZT12-15 0 0 0 ZT16-19 6.40426 6.40426 6.40426 ZT20-23 6.12153 6.12153 6.12153