condition mean min max ZT0-3 15.350275 15.0475 15.65305 ZT4-7 12.713049999999999 12.713049999999999 12.713049999999999 ZT8-11 12.89085 12.89085 12.89085 ZT12-15 0 0 0 ZT16-19 15.5515 15.5515 15.5515 ZT20-23 15.150549999999999 15.150549999999999 15.150549999999999