condition mean min max ZT0-3 4.145885 4.1379649999999994 4.153805 ZT4-7 4.2191 4.2191 4.2191 ZT8-11 4.09254 4.09254 4.09254 ZT12-15 0 0 0 ZT16-19 4.611025 4.611025 4.611025 ZT20-23 4.180295 4.180295 4.180295