condition mean min max ZT0-3 17.246274999999997 17.191399999999998 17.30115 ZT4-7 14.117650000000001 14.117650000000001 14.117650000000001 ZT8-11 15.931650000000001 15.931650000000001 15.931650000000001 ZT12-15 0 0 0 ZT16-19 24.156550000000003 24.156550000000003 24.156550000000003 ZT20-23 21.60275 21.60275 21.60275