condition mean min max ZT0-3 7375.524886 7375.524886 7375.524886 ZT4-7 8660.736643 8660.736643 8660.736643 ZT8-11 6494.35862 6494.35862 6494.35862 ZT12-15 6759.1697265 6759.1697265 6759.1697265 ZT16-19 6551.7487725 6551.7487725 6551.7487725 ZT20-23 5319.947509 5319.947509 5319.947509