condition mean min max ZT0-3 6.30162 6.30162 6.30162 ZT4-7 6.7770600000000005 6.7770600000000005 6.7770600000000005 ZT8-11 3.9700450000000003 3.9700450000000003 3.9700450000000003 ZT12-15 3.6039250000000003 3.6039250000000003 3.6039250000000003 ZT16-19 3.525615 3.525615 3.525615 ZT20-23 4.733385 4.733385 4.733385