condition mean min max ZT0-3 17.900000000000002 17.1811 18.92705 ZT4-7 15.87505 15.87505 15.87505 ZT8-11 14.603200000000001 14.603200000000001 14.603200000000001 ZT12-15 17.2443 17.2168 17.2718 ZT16-19 15.4583 15.4583 15.4583 ZT20-23 16.2267 16.2267 16.2267