condition mean min max ZT0-3 2.028145 2.028145 2.028145 ZT4-7 1.389485 1.389485 1.389485 ZT8-11 1.2428949999999999 1.2428949999999999 1.2428949999999999 ZT12-15 1.273835 1.273835 1.273835 ZT16-19 1.990845 1.990845 1.990845 ZT20-23 2.105035 2.105035 2.105035