condition mean min max ZT0-3 18.049999999999997 18.049999999999997 18.049999999999997 ZT4-7 19.7 19.7 19.7 ZT8-11 25.75 25.75 25.75 ZT12-15 16.85 16.85 16.85 ZT16-19 13.3 13.3 13.3 ZT20-23 4.949999999999999 4.949999999999999 4.949999999999999