condition mean min max ZT0-3 19.077472 19.077472 19.077472 ZT4-7 20.141883999999997 20.141883999999997 20.141883999999997 ZT8-11 21.701827 21.701827 21.701827 ZT12-15 14.9814615 14.9814615 14.9814615 ZT16-19 15.382225 15.382225 15.382225 ZT20-23 12.625309999999999 12.625309999999999 12.625309999999999