condition mean min max ZT0-3 7.2594825 6.697485 7.821479999999999 ZT4-7 5.9177800000000005 5.9177800000000005 5.9177800000000005 ZT8-11 7.182964999999999 7.182964999999999 7.182964999999999 ZT12-15 0 0 0 ZT16-19 7.873519999999999 7.873519999999999 7.873519999999999 ZT20-23 8.225775 8.225775 8.225775