condition mean min max ZT0-3 1.548321566 0.162425659 2.934217473 ZT4-7 8.182592526499999 7.0798160894999995 9.2853689635 ZT8-11 11.233248206999999 8.3175186905 14.1489777235 ZT12-15 16.71064878 15.232866255000001 18.188431305 ZT16-19 9.581961644 8.7233864 10.440536888 ZT20-23 6.732569714 6.2836121075 7.181527320500001