condition mean min max ZT0-3 16.380474 16.380474 16.380474 ZT4-7 18.820999 18.820999 18.820999 ZT8-11 22.811888500000002 22.811888500000002 22.811888500000002 ZT12-15 20.6289275 20.6289275 20.6289275 ZT16-19 31.162101999999997 31.162101999999997 31.162101999999997 ZT20-23 27.072834999999998 27.072834999999998 27.072834999999998