condition mean min max ZT0-3 17.411775 16.58755 18.236 ZT4-7 15.8047 15.8047 15.8047 ZT8-11 34.009100000000004 34.009100000000004 34.009100000000004 ZT12-15 0 0 0 ZT16-19 39.64105 39.64105 39.64105 ZT20-23 26.902949999999997 26.902949999999997 26.902949999999997