condition mean min max ZT0-3 4.419625 2.1988450000000004 5.562825 ZT4-7 1.7237200000000001 1.7237200000000001 1.7237200000000001 ZT8-11 2.5030900000000003 2.5030900000000003 2.5030900000000003 ZT12-15 3.194115 3.0047550000000003 3.383475 ZT16-19 4.516145 4.516145 4.516145 ZT20-23 6.46903 6.46903 6.46903