condition mean min max ZT0-3 1.471635 1.471635 1.471635 ZT4-7 1.4796865000000001 1.4796865000000001 1.4796865000000001 ZT8-11 2.456865 2.456865 2.456865 ZT12-15 3.2567399999999997 3.2567399999999997 3.2567399999999997 ZT16-19 4.209025 4.209025 4.209025 ZT20-23 1.84333 1.84333 1.84333