condition mean min max ZT0-3 13.221086666666668 5.44336 17.93965 ZT4-7 5.944725 5.944725 5.944725 ZT8-11 5.01181 5.01181 5.01181 ZT12-15 6.65716 6.10003 7.21429 ZT16-19 9.518229999999999 9.518229999999999 9.518229999999999 ZT20-23 15.9866 15.9866 15.9866