condition mean min max ZT0-3 87.491664 87.491664 87.491664 ZT4-7 75.332078 75.332078 75.332078 ZT8-11 57.3108555 57.3108555 57.3108555 ZT12-15 48.732845999999995 48.732845999999995 48.732845999999995 ZT16-19 15.8659405 15.8659405 15.8659405 ZT20-23 22.966182 22.966182 22.966182