condition mean min max ZT0-3 1.79860323175 1.6878680725000001 1.909338391 ZT4-7 2.44543493925 1.6020896740000001 3.2887802045 ZT8-11 5.54577969075 4.6065569795000005 6.485002401999999 ZT12-15 9.918648573250001 7.489128236500001 12.348168910000002 ZT16-19 7.209573334 6.703117561000001 7.716029107 ZT20-23 11.72151211325 10.1601558015 13.282868425