condition mean min max ZT0-3 23.685431 23.685431 23.685431 ZT4-7 33.767294 33.767294 33.767294 ZT8-11 35.3386905 35.3386905 35.3386905 ZT12-15 35.569677999999996 35.569677999999996 35.569677999999996 ZT16-19 33.9315725 33.9315725 33.9315725 ZT20-23 31.8402605 31.8402605 31.8402605