condition mean min max ZT0-3 7.671887 7.671887 7.671887 ZT4-7 7.5456795 7.5456795 7.5456795 ZT8-11 7.54378 7.54378 7.54378 ZT12-15 7.3826345 7.3826345 7.3826345 ZT16-19 8.080446 8.080446 8.080446 ZT20-23 8.0321665 8.0321665 8.0321665