condition mean min max ZT0-3 6.215511666666667 4.18577 7.913465 ZT4-7 2.7735700000000003 2.7735700000000003 2.7735700000000003 ZT8-11 1.463495 1.463495 1.463495 ZT12-15 3.0307475 2.810685 3.25081 ZT16-19 4.833565 4.833565 4.833565 ZT20-23 6.961705 6.961705 6.961705