condition mean min max ZT0-3 16.017825 15.2312 16.80445 ZT4-7 9.273085 9.273085 9.273085 ZT8-11 2.982125 2.982125 2.982125 ZT12-15 0 0 0 ZT16-19 7.052825 7.052825 7.052825 ZT20-23 11.221115000000001 11.221115000000001 11.221115000000001