condition mean min max ZT0-3 1.6670216666666668 0.545335 2.36464 ZT4-7 1.5290905000000001 1.5290905000000001 1.5290905000000001 ZT8-11 3.3535 3.3535 3.3535 ZT12-15 2.19684025 0.8868905 3.50679 ZT16-19 3.09051 3.09051 3.09051 ZT20-23 1.343879704 1.343879704 1.343879704