condition mean min max ZT0-3 18.6096 18.6096 18.6096 ZT4-7 12.403 12.403 12.403 ZT8-11 9.693795000000001 9.693795000000001 9.693795000000001 ZT12-15 13.95665 13.95665 13.95665 ZT16-19 21.32265 21.32265 21.32265 ZT20-23 19.498350000000002 19.498350000000002 19.498350000000002