condition mean min max ZT0-3 2.078357014 1.134942712 3.021771316 ZT4-7 1.7155183635 0.851542205 2.579494522 ZT8-11 9.9764112485 6.680950397 13.2718721 ZT12-15 10.051673522 9.939139607 10.164207437 ZT16-19 3.2031101809999996 2.7723702709999998 3.633850091 ZT20-23 1.5282870530000001 1.318762303 1.737811803