condition mean min max ZT0-3 8.86154 8.86154 8.86154 ZT4-7 6.234719999999999 6.234719999999999 6.234719999999999 ZT8-11 6.847835 6.847835 6.847835 ZT12-15 7.778840000000001 7.778840000000001 7.778840000000001 ZT16-19 8.631615 8.631615 8.631615 ZT20-23 8.273905 8.273905 8.273905