condition mean min max ZT0-3 4.166895 3.9941649999999997 4.339625 ZT4-7 3.1025650000000002 3.1025650000000002 3.1025650000000002 ZT8-11 6.076185000000001 6.076185000000001 6.076185000000001 ZT12-15 0 0 0 ZT16-19 6.7326 6.7326 6.7326 ZT20-23 4.57788 4.57788 4.57788