condition mean min max ZT0-3 20.859639 20.859639 20.859639 ZT4-7 24.4009405 24.4009405 24.4009405 ZT8-11 21.550106 21.550106 21.550106 ZT12-15 25.5514635 25.5514635 25.5514635 ZT16-19 20.4711625 20.4711625 20.4711625 ZT20-23 19.123534499999998 19.123534499999998 19.123534499999998