condition mean min max ZT0-3 8.821660000000001 7.40751 10.23581 ZT4-7 6.988175 6.988175 6.988175 ZT8-11 7.18234 7.18234 7.18234 ZT12-15 0 0 0 ZT16-19 9.871690000000001 9.871690000000001 9.871690000000001 ZT20-23 8.380845 8.380845 8.380845