condition mean min max ZT0-3 39.970225815 33.87271303 46.0677386 ZT4-7 27.353115817499997 25.03198595 29.674245685 ZT8-11 21.589542965 18.936830264999998 24.242255665 ZT12-15 8.6693594115 7.339022214 9.999696608999999 ZT16-19 17.77214811 14.825713805 20.718582415 ZT20-23 23.0774942 22.583910565 23.571077835