condition mean min max ZT0-3 6.912147 6.912147 6.912147 ZT4-7 7.876424999999999 7.876424999999999 7.876424999999999 ZT8-11 7.168661500000001 7.168661500000001 7.168661500000001 ZT12-15 7.1312964999999995 7.1312964999999995 7.1312964999999995 ZT16-19 6.8035605 6.8035605 6.8035605 ZT20-23 8.6234225 8.6234225 8.6234225