condition mean min max ZT0-3 2.112305 2.112305 2.112305 ZT4-7 2.336615 2.336615 2.336615 ZT8-11 2.4367650000000003 2.4367650000000003 2.4367650000000003 ZT12-15 2.631635 2.631635 2.631635 ZT16-19 2.661965 2.661965 2.661965 ZT20-23 1.78545 1.78545 1.78545