condition mean min max ZT0-3 6.248765458499999 6.247119442 6.250411475 ZT4-7 2.6163090657500003 1.5392193120000002 3.6933988195 ZT8-11 2.5345026915 1.9571090925 3.1118962905000003 ZT12-15 2.7967751505000003 2.6602083725 2.9333419285 ZT16-19 4.133561855 3.9622810315 4.3048426785 ZT20-23 4.647390486 4.4141989275 4.8805820445