condition mean min max ZT0-3 4.782185 2.75907 6.754379999999999 ZT4-7 4.16159 4.16159 4.16159 ZT8-11 4.3688 4.3688 4.3688 ZT12-15 4.4027825 4.053755 4.75181 ZT16-19 4.2975650000000005 4.2975650000000005 4.2975650000000005 ZT20-23 4.919565 4.919565 4.919565