condition mean min max ZT0-3 12.515769 12.515769 12.515769 ZT4-7 12.048961 12.048961 12.048961 ZT8-11 11.214182000000001 11.214182000000001 11.214182000000001 ZT12-15 11.0818905 11.0818905 11.0818905 ZT16-19 11.447281 11.447281 11.447281 ZT20-23 11.635528 11.635528 11.635528